1. Strip mine near Colstrip
2. Squall Line Sweeps Through Montana
3. Watershed of the Yellowstone River
4. *Triple Divide Peak in Glacier National Park
5. Oceanfront Property in Montana
6. *Mazama Ash Near Helena
7. Honey Car in Butte
8. *Chalk Cliffs in Central Montana
9. A Meteor Among Circumpolar Stars
10. *Recessional Moraines Near Turner
11. *The Cliffs of Crown Butte
12. *Ice Age Changes Path of the Missouri River
13. East Helena Superfund Site
14. Precipitation Map of Montana
15. *Madison Canyon Landslide
16. Lateral Moraine North of Missoula
17. White Cliffs of the Missouri
18. *Temperature Inversion in the Helena Valley
19. Why the Days Are So Short in December?
20. *Stromatolites Near Continental Divide
21. Sludge Injector Truck Fertilizes Fields
22. Mines in Little Rockies Are Visible From Space
23. *Jet Stream Delivers Balloon Bombs During WWII
24. How Glaciers Helped Form Flathead Lake
25. Igneous Dome in North-Central Montana
26. *Huge Iron Concretions in front of the Metra
27. Milltown Dam Removal
28. Montana Wind Energy Resources
29. Meltdown in Glacier Park
30. *An Oxbow Lake on the Hi-Line
31. The Berkeley Pit in Butte
32. A Septic Tank Near Montana City
33. Shorelines of Glacial Lake Missoula
34. Pedestal Rock Along White Cliffs Area of Missouri River
35. Giant Springs: An Artesian Situation
36. The Oldest Rocks Are In Western Montana
37. Tillite Found Among Pile of Erratics in North-Central Montana
38. Smelter Site Became the Old Works Golf Course
39. Logan Pass on the Continental Divde in Glacier Park
40. Evidence of Volcanism and Glaciation Along the Hi-Line
41. Weather Balloon Launch from Great Falls
42. Pollen Provides Clues About Past Climates
43. Shape of Land to Blame for Livingston's Strong Winds
44. *Lead Bullets Poison Eagles
45. *1935 Earthquakes Destroy Helena High School
46. Coalbed Methane Controversy
47. Counterclockwise Flow Around a Mid-Latitude Low
48. D-Day Moon
49. Carpenter Kicks 53-Yard Field Goal
50. *Limestone Wall Surrounds Little Rockies
51. Layers of Sediment from Glacial Lake Great Falls
52. *The Northern Lights
53. Chief Mountain
54. Storm Drains Are Not For Waste Disposal
55. Can you name these Montana rivers?
56. The K/T Boundary Near Jordan
57. Death By Dust In Libby
58. *SNOTEL Sites Measure Snow In Remote Areas
59. Slag Piles In East Helena
60. Dinosaur Discoveries Near Choteau
61. What causes the Chinook winds?
62. Canyon Ferry Dam on the Missouri River
63. Satellite View of Montana at Night
64. Jupiter and some of its moons
65. Which town has the coldest winters?
66. Aerial View of A Fault Scarp Near Helena
67. Decision Point for Lewis and Clark
68. An Alluvial Fan Near Ennis
69. Floodwaters Surrounded Glasgow in 1952
70. Goatlick Provides Minerals For Goats in Glacier Park
71. Where To Find Igneous Rocks In Montana
72. Radar Image Shows Tornado South of Malta
73. The Principle of Crosscutting Relationships
74. *Glacial Striations on the Ft. Belknap Reservation
75. Marlin, the Meteorite Man in Malta, Montana
76. The Belt Meteor Crater
77. Glacial Trough South of Red Lodge
78. Mountains of Conglomerate in Southern Montana
79. *Evaporation to Blame for Downbursts
80. *Geysers in Billings? Rhinos in Nebraska?
81. *Fata Morgana (mirage) from the CDT
82. The Great Falls of the Missouri
83. Grasshopper Glacier North of Yellowstone Park
84. Saline Seep Ruins Farmland
85. High Pressure to Blame for Dry Month in Montana
86. Lime Kilns Provided Mortar for Construction of the Capitol
87. The Best-Preserved Dinosaur Fossil in the World
88. Montana Counties Were Fallout Hot Spots During Cold War
89. Through the Guts of an Ancient Volcano
90. Glacier Park's Key Bed
91. *Rock Flour Needed to Make Glacial Milk in Cracker Lake
92. *The Madison Limestone: Montana's Rock of Ages
93. Great slabs of rock in the Belt Supergroup
94. Where cement comes from
95. Shatter cones from an ancient asteroid impact
96. How is electricity generated in Montana?
97. Wind Generators in Central Montana
98. Chalk Buttes in south-eastern Montana
99. Lewis and Clark Pass on the Continental Divide
100. Drumlin Field Resembles Tadpoles
101. Kettle Lake near Plentywood
102. *Native Americans Preferred Quartzite for Boiling Stones
103. Radiocarbon Dating Provides Clues about Montana's First People
104. *Ice Caves of Montana
105. Ringing Rocks of Montana
106. Smith Mine Disaster in 1943
107. *Ancient Ash in the Missouri Breaks of Central Montana
108. *Ancient Waterfalls Associated With Glacial Lake Great Falls
109. Tornado Wipes Out Ranch, Kills Two
110. Salinity of Surface Water in Earth's Oceans
111. Paleoecology Lab at Montana State University
112. Lone Peak Rock Glacier at Big Sky Ski Area
113. Fire, Floods Trigger Mass Wasting in Gates of the Mountains
114. *Hail Damage Path Visible from Space
115. *Snake Butte, A Hi-Line Landmark
116. *Microburst Flattens Trees North of Butte
117. Dike Cuts Through Eagle Sandstone
118. *Thin-Skinned Thrust Faulting Along the Rocky Mountain Front
119. Bakken Oil Field Visible from Space
120. Helena's Troubled Watershed
121. Gneiss in the Spanish Peaks
122. *Shonkin Sag Laccoltith
123. *Grinnell Glacier Moraine
124. *Scapegoat Mountain
125. Bighorn Canyon in Southeastern Montana
126. *Chinook Arch over Helena
127. *Marble Formed by Contact Metamorphism
128. Strange Flow of Rocks - A Rock Glacier beneath Mt. Powell
129. Fascinating Geology of Ear Mountain
130.*Kelvin-Helmholtz Clouds Over Helena
131. *Huge Pile of Erratics in North-Central Montana
132. *Special Conditions Needed for Rime to form
133. *Winter Count Recorded The Great Meteor Storm of 1833
134. The Big Flat sits on Flaxville Formation
135. *The St. Mary Canal System Feeds the Milk River
136. *The Snake Butte Boulder Train
More Pictures will be added from time to time.
Saturday, December 13, 2025
Montana's Earth Science Pictures (MESPOWs)
#8 - Chalk Cliffs in Central Montana (30-second video)
The Chalk Cliffs (above), located 25 miles north of Stanford are not chalk, but rather an especially light-colored sandstone. On the other hand, chalk is a soft type of limestone that forms from the accumulation of microscopic marine organisms, such as foraminifera and coccolithophores, which have shells made of calcium carbonate (calcite). When these organisms die, their shells sink to the seafloor, piling up to form a soft, white ooze. Over millions of years, the layers of ooze are compacted and lithified under pressure, hardening into chalk. The White Cliffs of Dover (England) are a famous outcrop of chalk.
Some beach . . .
In contrast, sandstones are composed of tiny rock fragments, primarily quartz, mixed with fragments of other minerals like feldspar, etc. The grains are typically glued together by natural cements such as silica (quartz), calcite, or iron oxide. The color and characteristics vary greatly, depending on the type of grains and cementing material, with iron oxides often creating red, yellow, or brown hues. Sandstones form in a variety of environments, including beaches, rivers, lakes, and deserts. The Chalk (NOT) Cliffs shown above are made of sand eroded from ancient mountains then deposited along the shore of an ancient sea, whereas many of the iconic sandstones in the soutwestern USA tell of ancient deserts.
The Virgelle sandstone . . .
The sandstone cliffs shown above are composed of a colorless quartz sand that was deposited near the shore of the Western Interior Seaway during the late Cretaceous period, which ended 66 million years ago. Cross-bedding suggests the sand was transported by coastal streams draining eastward as the seaway retreated. The cliffs are made of Virgelle sandstone - technically it's the Virgelle member of the Eagle formation. It is named "Virgelle" because the distinct sandstone was first identified near the tiny town of Virgelle, located along the Missouri River near Big Sandy (several miles west of Highway 87). An even more impressive outcrop of the Virgelle can be found along the White Cliffs of the Missouri, from Coal Banks (near Virgelle) to Judith Landing - a great canoe trip! The Virgelle is a "lower" member of the Eagle formaton, which means the Virgelle layers are near the bottom (older, deposited before other layers in the Eagle formation). The Virgelle varies in thickness but generally ranges from around 100 to 125 feet, reaching over 200 feet in certain areas. The Eagle formation outcrops in many places in central and eastern Montana - The Rimrocks of Billings are Eagle sandstone.
Right: Sketch borrowed from Roadside Geology of Montana, showing the location of the Virgelle Sandstone beach adjacent to the Western Interior Seaway during Cretaceous time. - Hyndman and Thomas, 2020
Stratigraphy . . .
In this part Montana the Virgelle and a transitional layer below it (Telegraph Creek Formation) were deposited on top of sea floor mud that became the Marias River Shale. The sediment of the Marias is composed of finer grain sediments deposited when the sea was deeper here (farther from the shore). Another shale, the Claggett, sits on top of the Virgelle, indicating the area went from being beneath deeper water (Marias shale) to being near the shoreline (Virgelle sandstone), and then back to a deeper environment (Clagget shale). The Western Interior Seaway was a shallow sea whose shoreline was everchanging. CLICK HERE to watch a video of the fluctuating Western Interior Seaway.
Term: stratigraphy
CLICK HERE to see my photo album from a hike onto the Chalk Cliffs (includes several drone photos).
Below: Google Earth view of the Chalk Cliffs - The "X" marks the area I explored.
Below: Here is how the Eagle formation (including the Virgelle member) is described on the MBMG Geology Map of Montana.
Friday, December 12, 2025
#1 - Strip Mine Near Colstrip, MT
This photo shows a coal "strip mine" located near Colstrip, 90 miles east of Billings. Known as the Powder River Basin, this region contains thick seams of coal that formed as coastal swamps were buried by sediments millions of years ago. Strip mining can be used in this area because the coal seams are closer to the surface than seams located in the eastern United States where underground coal mines are more common. Strip mining is much safer because miners do not have to go underground where collapses, gas explosions, and lung diseases are risks.
The majority of coal mined in the U.S. is from seams varying in thickness from 3 to 10 feet, although the seams in the Powder River Basin of southeastern Montana and northeastern Wyoming average 40 feet in thickness. Mining of this region's low-sulfur coal increased drastically in the early 1970s when the Clean air Act mandated that industries decrease emissions of sulfur dioxide, a gas that contributes to acid rain. The graph on the right shows how much coal was mined in Montana during the 1900's. The increase in the 1970's centered around the town of Colstrip - and in Wyoming, the town of Gillette became the hub of coal mining activity. Although Montana has more coal than any other state, Wyoming leads the way in the amount of coal mined. One reason for this is that Montana has a significant tax on coal sales, called the "Coal Severance Tax." Money collected from this tax is saved in a state "trust fund" for future generations.
What is it used for?
Montana's coal is primarily used for electricity generation. Some is burned at coal-fired power plants in Colstrip, with most mined coal (around 75%) shipped by rail to large, coal-fired power plants in the Midwest and Western states (like WA, OR), or exported internationally to countries like Japan, South Korea, and China for electricity generation. If you live in southern or western Montana, you've probably seen long trains loaded with coal on their way to these places.
Fossil fuels.
Coal, along with petroleum (oil), and natural gas are called "fossil fuels." Oil is used to make liquid fuels for trains, planes, and automobiles, and much of the natural gas is piped into homes where it is burned to heat air and water in furnaces and water heaters. Coal is not our only source of electricity, but coal-fired generators like those at Colstrip provide much of the electricity used in Montana. Hydroelectric dams provide the next biggest portion for Montanans. Nuclear plants (none in Montana) and wind generators are two other sources of electricity in the USA. Fossil fuels have been a focal point in the debate over climate change because carbon dioxide is emitted into the air as fossil fuels are burned. According to the "greenhouse theory" this carbon dioxide traps heat in our atmosphere, warming the world.
One Strip at a Time.
In the photo at the top of this page overburden has been removed, exposing a seam (layer of coal) that is ready to be mined. The long pile of rock (spoils) to the right is material recently removed from the strip of coal. The spoils sit atop the seam that was mined before the strip shown in the photo was exposed. After the exposed strip of coal is removed, the area to the left will become the next "strip". Its topsoil has already been taken away and stored. Next the coal will be removed and then eventually the broken up rock will be put back, smoothed out, the topsoil will be replaced, and the area will be seeded with native plants.
Term: overburden
Can you figure it out?
The diagram below is a cross-section of an area very similar to the area shown in the photo. Try to figure out which of the lettered areas on the diagram correspond to the following: coal, solid sedimentary rock layers, spoils, undisturbed topsoil, subsoil that has been returned, broken up rock that has been re-shaped, topsoil ready to be replanted, undisturbed subsoil.
#59 - Slag Pile in East Helena
If you've traveled through East Helena, you probably noticed the huge pile of black material at the ASARCO Smelter along the highway. The material, called "slag", is waste product produced as ASARCO removed lead from the ore.
Getting the lead out . . .
For more than a century, crushed ores containing galena (PbS) were brought to East Helena from as far away as Chile and Korea. Once at the smelter, the ores were "roasted" in order to remove the sulfur. The sulfur combined with oxygen to form a gas called sulfur dioxide, a pollutant that contributes to acid rain. A law called the Clean Air Act, which went into effect in the early 1970s, required that industries like the smelter remove this emission. A pollution-control device called a "scrubber" had to be installed to do this.
A density thing . . .
The roasting formed a material called "sinter," which was a mixture of lead oxide (PbO) and other rock materials. Next the sinter had to be melted. Crushed limestone and quartz were added to make it easier to melt the mixture. Once the material was melted, the heaviest stuff (lead) would sink to the bottom of the tank. The molten lead was then drained out through openings in the bottom into molds where it solidified.
Separation by melting . . .
This separation by melting is called smelting. The rest of the molten material, which had been floating above the layer of lead, also solidified, forming the black waste product called slag. For years the slag was disposed of by dumping it along the edge of the smelter property.
Other metals too . . .
Until its closure in the spring of 2001, the ASARCO Smelter shipped 10-ton pieces of lead by rail to a refinery back east. The refinery was able to separate trace amounts of other valuable metals such as gold and silver. In a typical year (early 1990s) the smelter's bullion yielded the following:69,000 tons of lead, 3,500 tons of copper, 690 tons of arsenic, 150 tons of bismuth, 20,000,000 oz. of silver, 200,000 oz. of gold
Anaconda's slag . . .
The smelter in Anaconda was designed to extract copper from the ores mined in Butte. The texture of Anaconda's slag is much different than the slag in East Helena. East Helena's slag is very "blocky," with pieces varying from fist-size to much larger. In Anaconda the slag is more like sand because the molten slag was spilled into water, causing it to harden and shatter into sand-sized pieces. In fact Anaconda's slag has been used in sand traps at the famous Old Works Golf Course.
To find out what might be in store for the future of the slag and the smelter site CLICK HERE (includes an article and short video from 9/23/25).
Term: smelting
Trivia . . .
Country Music Hall of Fame singer, Charlie Pride, once worked at East Helena's smelter and starred on the Smelterite baseball team.
Below: An older photo of the ASARCO Smelter site. The stacks were toppled several years ago, but the slag remains.
#81 - Fata Morgana from the CDT
Several years ago a friend and I did a snowshoe hike from Stemple Pass to Flesher Pass (near Helena) on the Continental Divide Trail (CDT). The temperature was pleasant, the snow was perfect, and it was sunny with no wind - but the best part of the hike was witnessing an unusual atmospheric phenomena known as Fata Morgana.
It's a trap! . . .
“Fata Morgana” is so-named because it is the Italian name for the Arthurian sorceress Morgan le Fay, and it was believed that she created these illusions of distant castles or land to lure sailors to their deaths. In reality all mirages are due to refraction (bending, redirecting) of light from distant objects. What we observed during the hike was the result of light from distant mountains being refracted as it traveled through layers of air that had different temperatures. The temperature inversion that blanketed the area that week was the major factor that allowed the sorceress to do her handiwork.
Inversion? . . .
During winter months, the mountain valleys of western Montana are prone to inversions. They're called inversions because they are upside-down situations. The temperature of the atmosphere NORMALLY gets colder as you get farther away from the surface. However during inversions, air near the surface is colder than the air above. Inversions tend to form during stretches of clear, calm, very cold weather. Without clouds, heat given off by the earth escapes easily into space, causing a layer of cold air to develop at the surface. An especially strong inversion was present in the Helena-Lincoln area when the Fata Morgana photos were taken - There was a layer of very cold air in the valleys with warmer air above.
Illusionary beauty . . .
Fata Morgana is a type of mirage known as a superior mirage. All mirages are caused by the refraction (curving or redirecting) of light as it passes through layers of air with different temperatures and densities, creating false images, like seeing "water" on a hot road or distant objects appearing to float. This happens because hot air (less dense) and cool air (denser) refract light differently, making the brain perceive bent light as if it traveled in a straight line from a different location (diagram). This bending or redirecting occurs because light travels at slightly different speeds when passing through different mediums. When there are stark changes in air density due to layers of air having different temperatures, this can create the illusion of distant objects or water. For instance, on a hot day, the air near on a paved highway is much warmer and less dense than the air above it, causing light rays to bend upwards, which creates the illusion of water on a road’s surface - this is an inferior mirage. The intricate nature of Fata Morgana involves multiple curved light rays converging towards the observer's eye. This convergence creates an illusionary effect, making objects appear inverted or smeared upwards into towering cliffs as shown in the photo atop this page.
Term: refraction
CLICK HERE to learn more about Fata Morgana (Wikipedia)
CLICK HERE to access my blog and photo tour of the hike we were doing when we witnessed the Fata Morgana.
CLICK HERE to watch a short YouTube video that demonstrates refraction.
Below: The situation we witnessed was more complicated than the one illustrated below, but the diagram may help you understand how refraction is involved.
Below: These two photos taken from the same vantage point show a mirage effect with Three Buttes on the Ft. Belknap Reservation.
Thursday, December 11, 2025
#7 - When you gotta go, you gotta go!
How sweet it is . . .
The photo shows one of the "honey cars" that served as toilets for the men as they worked the mines deep beneath the surface of Butte. These "sweet" smelling rail cars consisted of iron tanks with toilet seats on top. The rail car design allowed the honey cars to be moved in and out of the mines on the same system of rails that was used to haul copper ore to the surface.
Hazards of working the underground mines . . .
The work of the underground miners was both demanding and dangerous. Occasionally parts of the mine would collapse, burying men beneath large pieces of rock referred to as "Dugans" (named after the family that owned the local mortuary). Fire was also a danger. In 1917 an underground fire 2,400 feet below the surface in the Granite Mountain Mine* killed 168 men. For those who survived careers underground, years of inhaling the dusty air often caused lung diseases that stole years away from retired miners.
Electrifying the USA . . .
The underground mines of Butte dominated world copper production between 1887 and 1920. By 1916 over 14,000 miners worked the underground mines on rotating shifts around the clock. At one point about a forth of the world's copper was coming out of Butte. As result, Butte is sometimes called "the city that electrified a nation" because Butte copper was used as wiring in homes. The light bulb had been recently evented and people all over the country wanted the new technology. By 1950, over 400 underground mines, consisting of several thousand miles of interconnected workings, had operated or were operating. The last underground mine closed in 1981.
NOTE: The photo was taken at the World Museum of Mining which is located near the campus of Montana Tech in Butte.
Terms: ore, open pit mine
#12 - Ice Age Changes Path of the Missouri River
Doesn't make sense . . .
The Milk River starts in Glacier Park, flows up into Canada and then returns to Montana northwest of Havre. Its valley is small, as you would expect for such a small river. However, a few miles east of Havre the valley of the Milk River suddenly becomes very wide, which is very unusual! From there to where it empties into the Missouri near Glasgow, the little river meanders along in the spacious floor of a broad valley that it could not have eroded. There is no corresponding change in resistance of the bedrock, so their had to be some explanation for the discrepancy.
A Hand-Me-Down Valley . . .
Shortly after the turn of the century geologists pointed out that the broad valley of the Milk River from Havre to Glasgow is about the size of the Missouri River valley below (east of) Ft. Peck, and that the Missouri River flows through a narrow canyon for a long distance between Ft. Benton and Ft. Peck. They suspected that the Missouri River may have occupied the broad valley along the Hi-Line until the ice pushed it south during a recent ice age, and then after the ice age the Milk River found that old pre-ice age valley of the Missouri River.
Missing link found . . .
More evidence was found, supporting the hypothesis. Another oversized valley, the valley of Big Sandy Creek south of Havre, was studied and determined to be a portion of the ancient valley that connected the current Missouri to its old valley on the Hi-Line. The ancient valley was not obvious at first because it was hidden beneath gravels brought to the area by the continental glacier and then transported again by meltwater as the ice age ended. More field work revealed the final connecting segment of the abandoned Missouri valley near Havre, which was also buried beneath glacial sediments. Mystery solved!
Term: stream channel
#11 - The Cliffs of Crown Butte
Volcanic past . . .
The photo above shows the cliffs of Crown Butte a flat-topped butte located 20 miles west of Great Falls. Both Crown Butte and its larger neighbor, Square Butte, are formations called laccoliths. Laccoliths are formed when magma is injected between layers of sedimentary rock beneath the surface. The magma, which came from an ancient volcano centered 10 miles south of Cascade, worked its way through cracks in the bedrock to get here. Eventually the magma hardened, forming a very durable type of rock that has survived millions of years of erosion. In the meantime the softer sedimentary rocks (sandstones, etc.) that once covered the laccolith have been eroded away, exposing the laccoliths as buttes that can be seen throughout central Montana.
Layered igneous complex . . .
Although layers are usually associated with sedimentary rock, the igneous rock of the butte is made up of very distinct layers. Evidently, the magma filled the laccolith in "pulses" with each new pulse forming another layer. Closer examination reveals a thin lighter-colored layer between each of the thicker, darker layers. This separation within each pulse may have happened as a result of differences in the densities and/or freezing points of various minerals in the magma. Another theory is that the thin light-colored layers formed as a result of water soaking in from the sandstone above before the next layer of magma was injected.
Publc access . . .
The Nature Conservancy purchased Crown Butte in order to preserve the natural grassland ecosystem located on top of the butte. Except for an occasional hiker, the ecosystem sits undisturbed about 1,000 feet above the surrounding prairie.
CLICK HERE to access my blog and photo tour - Crown Butte is one of my favorite places!
Terms: laccolith, intrusive formation
#2 - Classic Squall Line of July 8, 2002
This radar image shows a squall line that swept through central and eastern portion of Montana on the evening of July 8, 2002. Blue areas indicate light precipitation, green areas indicate moderate precipitation, and the red areas show where precipitation is intense. The image was captured by the National Weather Service's Radar device located in Glasgow. The N.W.S. has radar in Glasgow, Great Falls, Billings, and Missoula. These cities were selected because they are far enough from each other to give the N.W.S. good coverage of the entire state.
Somewhat unusual in these parts . . .
A "squall line" is a line of thunderstorms that forms along a cold front as cooler air pushes into very humid, warmer air. Since air in the Midwest and southeastern United States tends to be more humid than in Montana, squall lines are much more common in these regions.
Rising humid air is the key . . .
Where cooler air is pushing into warmer air along a cold front, the warmer air rises because it is lighter. As this warmer air is forced upward, it cools by expansion. Eventually the cooling causes the vapor (humidity) in the rising air to condense, forming cloud droplets or ice crystals. The changing of vapor to liquid or solid releases heat which helps the air continue to rise, and the cycle continues.
It just kept going . . .
If the warmer air is especially humid as it was on July 8, a line of dangerous thunderstorms may sweep through an area. Since this cold front moved eastward, this squall line also moved eastward, causing lightning, hail, strong winds and even a threat of tornadoes across much of Montana.
Term: cold front
Below: This is a G.O.E.S. East Satellite view of the squall line at 5 pm MDT on July 8, 2002 - The same storm shown on the radar image above. The line of thunderstorms extends from southwest Saskatchewan toward northcentral Wyoming.
#3 - Watershed of the Yellowstone River
This image shows all the area that sends runoff into the Yellowstone River. This land is referred to as the Yellowstone River's "watershed", "drainage basin", or just "basin". Any rain or snow within the watershed that does not evaporate or soak into the ground will eventually end up in the Yellowstone River. Unfortunately, chemicals (fertilizers, herbicides, etc.) can also be carried into the river with the runoff. The primary source of water for the Yellowstone River is winter snow that falls in mountains within the basin during the winter. The flow of water (a.k.a. "discharge") in the Yellowstone is usually greatest in June when the snow in the mountains is melting rapidly.
Getting started . . .
As you might expect, the "headwaters" (starting point) of the Yellowstone River are in Yellowstone Park. The river flows northward out of the Park to Livingston. There it turns to the east, flowing toward North Dakota. The Yellowstone's larger tributaries are also shown on the map, and each of these has its own watershed. A large portion of the Bighorn and Powder River watersheds are located in north-central Wyoming.
Montana's Big Three . . .
The western third of the Montana drains into the Clark Fork River, and most of northern Montana empties into the Missouri River. Since the Yellowstone joins the larger Missouri River in North Dakota, the Yellowstone's watershed is considered to be part of the Missouri's watershed. Since the Missouri joins the Mississippi near St. Louis, its watershed is part of the Mississippi's. Unless it evaporates or is removed for use by cities or farmers, runoff from the Yellowstone River's watershed will end up in the Gulf of Mexico.
Terms: runoff, tributary
#4 - Triple Divide Peak in Glacier Park
Like the Matterhorn . . .
The peaks shown in the photo are glacial horns located in Glacier National Park. These pyramid-shaped features are formed as three or more glaciers erode the sides of a single mountain. The larger peak in the background is Mt. Stimson and the smaller horn in the center is called Triple Divide Peak. Triple Divide Peak was so-named because runoff from each of its three sides drains to a different watershed. (Runoff is melted snow or other forms of precipitation that drain off the land.) Melted snow from the west slope (left side) flows toward the Gulf of Mexico, runoff from the northeast slope (right) flows toward the Hudson Bay, and the southwest slope (behind the peak) drains to the Pacific.
The photo at the top of this page was taken near a ridge separates the Gulf of Mexico and the Hudson Bay watersheds (drainage basins). Such areas are known as "divides". Divides are higher areas (not always distinct ridges) that separate drainage basins. The most famous divide, The Continental Divide (a.k.a. the Great Divide), is also shown in the photo. The map on the right shows the divides that separate our continent's drainage basins (watersheds). Triple Divide Peak is labelled. Click on the map to enlarge it.
More about Triple Divide Peak . . .
CLICK HERE for an account of two hikes to the summit of Triple Divide Peak (including a linK to a photo tour).
Below: That's me walking along the Continental Divide between the Hudson Bay and Pacific Ocean watersheds on my way to the summit of Triple Divide Peak.
Terms: (drainage) divide, watershed
#5 - Ocean Front Property in Montana
When dinosaurs roamed . . .
During much of the Cretaceous Period (144 to 65 million years ago) a large portion of Montana was covered by the waters of a shallow, inland sea called the Western Interior Seaway. The sea was formed as west-central North America was subsiding to an elevation below sea level. As this sinking occurred the area filled with water from the Gulf of Mexico and the Arctic Ocean.
Source of the sediment . .
Between 80 and 40 million years ago, tectonic forces were building the Rocky Mountains in western Montana and Idaho. Rivers flowing eastward from these mountains transported massive amounts of sediment (sand, silt, clay) to this sea. As the land cycled between periods of uplift and subsidence, the seaway expanded or shrank, resulting in dramatic east-west shifts in the location of the coastline. CLICK HERE to watch a video of the fluctuating Western Interior Seaway.
Where do I drop you off? . .
Changes in the location of the coastline also caused changes in the type of sediment deposited in different areas. . . Sand was deposited closer to the coast, whereas silts and clays settled to the bottom in deeper waters. Watch this animation. As layers of sand, silt and clay became buried, they were compressed and turned into the sedimentary rocks found today in central and eastern Montana, and throughout the rest of the west-central United States. For example, the "Rimrocks" of Billings are made of sand deposited at or near the shoreline of the ancient Western Interior Seaway.
Terms: subsidence, deposition
#9 - A Meteor Among Circumpolar Star Trails
Robin Loznak took this photo for tThe Daily Interlake from the summit of Big Mountain near Whitefish. She pointed her camera at Polaris (The North Star), and then left the shutter open for 70 minutes, recording the motion of stars in the northern part of the sky. Such motion is referred to as "apparent" because it is not caused by the movement of the stars, but rather the spin of the Earth on its axis. It's like being on a merry-go-round and thinking that your surroundings are moving. The Sun and Moon move across our for the same reason. Since Polaris is directly above the North Pole, it stays put while the other stars seem to circle around it - They're referred to as circumpolar stars.
A rock among stars . . .
The straight bright line is a meteor (a.k.a. "shooting star"). Meteors are not stars at all. Instead they are small rocks that burn up in our atmosphere as they are pulled in from space by our planet's gravity. On any night, at any location, a few meteors can be seen each hour. Occasionally, intense meteor displays fill the sky with tens, hundreds, or even thousands of meteor trails. These displays, called meteor showers, can be predicted because they repeat every year when Earth passes through an area where a comet has passed through. The bits of debris left behind by the comets, most no larger than a grain of sand, create a spectacular light show as they enter the earth's atmosphere. The meteor in this week's photo was part of the Perseid Shower that occurs every year around August 12-13 as a result of debris left behind by Comet Swift-Tuttle.
Term: circumpolar stars, meteoroid
#13 - East Helena Superfund Site
For more than 100 years emissions from the ASARCO Lead Smelter caused lead to be deposited in the soils of East Helena. Microscopic lead particles were released from the tall stacks that stood on the smelter property until 2009. At the smelter, which closed in the late 1990s, tall stacks were used to put the pollution higher into the atmosphere where winds would carry it away and spread it out more. Unfortunately, a significant amount of lead ended up falling in the community of East Helena where it became part of the soil. As children played they may have inhaled some of the dust (including lead particles). Some of the lead would dissolve in the moisture in their lungs where it would be absorbed into their blood.
In 1984 East Helena was added to the EPA's (Environmental Protection Agency) Superfund Priorities List. Superfund sites are places that must be cleaned up because they pose a risk to human health and/or the environment.
Lead in the bodies of children . . .
Testing in 1975 indicated that children in East Helena had elevated levels of lead in their blood as result of inhaling dust from lead-contaminated soils. During the clean-up, which took place mostly in the 1990s, soil from over 700 yards was replaced. The soil replacement program continued to take place as children moved into houses where soils were contaminated.
Middle Photo: New topsoil was brought in.
Bottom photo: Finally, sod was placed on top of the new soil.
CLICK HERE to Watch the stacks come down. (YouTube Video 2:51)
Terms: Superfund Site, smelting
#14 - Precipitation Map of Montana
This map shows average annual precipitation amounts for Montana from 1961-1990. As you can see, precipitation amounts vary greatly throughout the state. If you were to compare the map shown above with one that shows the locations of mountains, you would see a strong correlation between mountains and areas of heavier precipitation. As air moves across Montana, mountains make the air rise. As it rises, the air cools by expansion. If there is enough humidity (vapor) in the air, this cooling will cause cloud formation and precipitation. When mountains provide the lift needed to cause precipitation, it is referred to as "orographic" precipitation. On the other hand, as air moves down into valleys, it becomes warmer by compression. As a result, valleys like the Helena Valley may get less than 15 inches of precipitation per year, whereas the surrounding mountains receive much more.
The prevailing winds influence which side of the mountains will have the most precipitation. In Montana, winds usually blow from west to east (the "westerlies"). For this reason, the western slopes of the mountains where air is rising can expect more precipitation than the the eastern slopes where air is sinking. A dramatic example of this can be seen in the Glacier Park area. There the westerlies encounter the high mountains of the park, causing tremendous amounts of precipitation to fall in places like Logan Pass (over 80 inches of precip.). Then as the air continues eastward it descends into the Browning area where precipitation is much less likely (less than 20 inches of precipitation).
The image on the right shows the shape of the land. Compare it to the precipitation map at the top. Do you see a correlation?
Term: rainshadow
#15 - Montana's Greatest Earthquake Disaster
The Night the Mountain Fell* . . .
This photo, taken 20 miles northwest of West Yellowstone, shows the Madison Canyon Landslide. The landslide happened as result of a magnitude 7.5 earthquake near Yellowstone Park at 11:37 pm on August 17, 1959. Tragically, a campground located on the Madison River was buried by the landslide, killing 24 people. Only five bodies were recovered. The rest are presumed to be buried beneath the landslide. This photo on the right was taken the day after the quake for the Deseret News (Salt Lake City).
The fallen mountain also blocked Highway 287 and dammed the Madison River, causing the formation of Earthquake Lake (a.k.a. Quake Lake). There was concern that the water would eventually overflow and wash away the landslide. This would have caused a flash flood in Ennis (40 miles downriver). A crew from the Army Corp of Engineers cut a channel through the landslide to prevent this from happening. Today a visitor center sits on the landslide, and in places the tops of dead trees can still be seen poking through the surface of the lake.
NOTE: The Madison River is a tributary of the Missouri River. The Madison, the Gallatin and the Jefferson Rivers join near the town of Three Forks, Montana to form the Missouri River.
Term: Army Corp of Engineers
*The Night the Mountain Fell is the title of a book about the disaster, written by Edmund Christopherson in 1960.
CLICK HERE to see many more historic photos of the area impacted by the earthquake.
#17 - White Cliffs of the Missouri
Eagle Creek Campground is one of the great campsites in Montana. It is located near the place where Eagle Creek empties into the Missouri (about 30 miles east of Ft. Benton). The White Cliffs in the background owe their existence to sand deposited near the shore of a shallow sea that extended from the Artic Ocean to the Gulf of Mexico. Called the "Western Interior Seaway", the sea existed from about 90 million years ago until about 70 million years ago.
When Dinosaurs Wandered the Area . . .
Apparently the shallow Western Interior Seaway experienced changes, which caused it to shrink and expand. These resulted in fluctuating depths and migrating coastlines. As rivers laden with sand, silt and clay emptied into this sea, the larger pieces (sands) would have settled to the bottom first. So, when the Eagle Creek area was at or near the coast, sands were deposited here as beaches and/or offshore sand bars. The smaller sediments (clays, silts) would not have settled right away, instead settling to the bottom of the sea in deeper waters farther away from the coast.
Same Layer, Different Location . . .
The same formation (layer) can be seen in Billings where it is known as the "Rimrocks". Geologists have named the layer (or series of layers) the Eagle Formation after the Eagle Creek area shown in the photo above and depicted in the Monte Dolack painting below.
When the coast was located farther to the west, the sea would have been somewhat deeper here. As a result of this deeper environment, this would have been a time when smaller particles such as silts, and clays were deposited here. Those materials make up the layer known as the Marias River Shale shown in the smaller photo of the Eagle Creek area below as well as on the painting. To see 40 photos from a trip through the White Cliffs (Coal Banks to Judith Landing; 3 days - 2 nights) in October 2012, CLICK HERE.
Claggett Shale . . .
Mountain Building (and the subsequent erosion) to the west of here provided an abundant source for the sands, silts, and clays deposited in this part of central Montana. The rock layers seen along the river tilt gently to the east, so as travelers move downriver (eastward), they see increasingly younger rock layers along the river. The photo below, taken about 25 miles downriver from the one above, shows the Eagle sandstone beneath the younger Claggett shale. The shale is made of finer sediments, which were deposited when this area was deeper and farther from the shore. Even farther downriver, the Eagle sandstone is below the surface so it cannot be seen along the river.
#18 - Helena Valley Temperature Inversion
Its a winter thing . . .
Inversions tend to form during stretches of clear, calm, very cold weather. Without clouds, heat given off by the earth escapes easily into space, causing a layer of cold air to develop at the surface. If the inversion persists, air quality can become a problem as the cold, stagnant layer near the surface fills with pollutants such as smoke from wood-burning stoves or emissions from automobiles. Eventually a storm passes through, blowing the polluted air out of the valley.
Below: Members of the Helena High Outdoors Club look down on the city of Helena. A foggy inversion layer is illuminated by city lights.
The lower part of the Earth's atmosphere, called the troposphere, is heated from the ground up by heat given off by the Earth. As sunlight shines of the Earth's surface some of the energy is absorbed and changed into heat. Eventually this heat is given off in the form of waves (infrared). If you wanted to get real fancy, you could say that "the surface radiates infrared energy". You also give off heat, and so does a baked potato. The closer you hold your hand to the surface of the hot potato, the warmer your hand feels. The same is true with the Earth. Usually air that is closer to the surface (the source of heat) is warmer than air that is farther away from the surface - Unless there is a temperature inversion.
Upside-Down . . . .
During winter months, the mountain valleys of western Montana are prone to inversions. They're called inversions because they are upside-down situations. Since the atmosphere is warmed from the bottom up by heat given off by the Earth, the temperature of the atmosphere NORMALLY gets colder as you get farther away from the surface. However during inversions, air near the surface is colder than the air above. Local hikers know this means that it can be 5-10 degrees warmer on top of the mountain than it is down at the trailhead.
Recipe for a temperature inversion - The three "C's". . .
Mountain valleys serve as "sinks" where cold, dense air may sit for several days. They develop during clear, calm, cold nights - especially in December and January. Clouds act like a blanket, keeping much of the heat given off by the Earth close to the surface. However, on clear nights this heat escapes quickly out to space, and air at the surface becomes cold (and heavy). The low angle of the Sun in December and January prevents this valley air from heating up during the days. Snow cover, which reflects sunlight, and the shortness of winter days also help prevent it from warming. If the inversion persists for several days, air quality worsens as the stagnant, cold air fills with pollutants such as smoke from wood-burning stoves or emissions from automobiles.
Check out this album of photos from a November 2015 temperature inversion, including several of a mirage known as Fata Morgana. The mirage photos were taken on a hike between Stemple Pass and Flesher Pass, and those overlooking Helena were taken the next day.
CLICK HERE to watch a 1-minute VIMEO video, showing a temperature inversion in the Helena Valley during December of 2017.
Term: infrared radiation, emissions
#19 - View of Earth during the Winter Solstice
This view of Earth helps depicts the Earth on the Winter Solstice (around December 21 each year). It shows why days are so short and nights so long this time of year. To fully understand the shortness of our days, here's a few things to keep in mind:
1. Earth orbits the Sun once every 365.25 days.
2. The Earth's axis is tilted 23.5 degrees* (see NOTE below). If it weren't, there would be no seasons and every place in the world would have 12 hours of daylight and 12 hours of darkness every day of the year. A common misconception about the seasons is that they are caused by Earth being closer or farther from the Sun at different times of the year. THAT IS NOT CORRECT. In fact the Earth is about 3 million miles closer to the Sun in early January than it is in early July! The average distance from the Earth to the Sun is 93 million miles.
3. The Earth spins on its axis once every 24 hours. This axis runs through the Earth from the North Pole to South Pole.
4. Around December 21, Earth reaches the position on its orbital path where the Northern Hemisphere is tilted away from the Sun. Six months from now, Earth will be on the opposite side of the Sun and our hemisphere will be "leaning" toward the Sun.
Good news and bad news . . .
As shown on the image, on December 21, residents of Helena (star) could have observed sunrise at 8:09 AM. (The large yellow circle shows the path of Helena during the 24 hours it takes Earth to spin on its axis.) As Earth continued to spin, Helena moved into darkness (sunset) at 4:43 PM. So, on this, the "shortest day" of the year, Helena experienced only 7.5 hours of daylight followed by 16.5 hours of darkness. In comparison, Anchorage, Alaska (A) would have experienced about 6 hours of daylight (sunrise at 10:14 AM, sunset at 3:41 PM). The good news is that after December 21, the amount time that Montana gets to spend in the Sun has been increasing by minutes per day. This trend continues until mid-June.
NOTE: The term "solstice" means "Sun stops." This term is used for December 21 because this is the day that the Sun stops getting lower in the sky (also directly related to Earth's tilt and the position of Earth on its journey around the Sun). This day is also the first official day of winter.
*NOTE: The tilt of Earth's axis does change slightly over tens of thousands of years, but the change during the course of one year is insignificant.
Term: equinox
#20 - Fossils Revealed As Glacier Melts Away
Above: Geologist Callan Bentley lies on the surface of the Grinnell Glacier cirque within several hundred feet of the Continental Divide in this 2007 photo. The strange circular shapes are ancient colonies of algae called stromatolites, which until recently, were covered with ice.
Cabbage Heads . . . The photo below was taken just few miles away from the top photo, on the opposite side of the divide along the Highline Trail in Glacier Park. Although this location is approximately 5,000 feet above sea level, it contains fossils of algae colonies (blue-green algae; aka cyanobacteria) that lived in a shallow sea around 1.4 billion years ago. The algae formed in an environment similar to what exists in the Florida Keys today. The fossil stromatolites have shapes and internal structures similar to ones that live in present-day seas. The outcrop in the photo below contains excellent examples of stromatolites that resemble heads of cabbage.
Stromatolites are mound-like, multi-layered colonies of algae (blue-green algae; aka cyanobacteria). The formation of the layered mounds has to do with the way they change the chemistry of the shallow water they live in. Photosynthesis in the cyanobacteria removes carbon dioxide from the surrounding water, causing calcium carbonate to precipitate onto their slimy, mat-like colonies. The calcium carbonate, along with grains of sediment (silt, etc.), stick to the bio-film layer that covers the colonies. As they continue to grow upwards through the sediment, a new layer forms. This process occurs over and over again, creating layered mounds, columns, or sheets.
Gases and Rocks . . .
Fossils of different species of stromatolites can be found in different areas of the park. It is believed that stromatolites that lived in the Precambrian played a major role in increasing the amount of oxygen in the atmosphere of the primeval Earth ("The Great Oxygenation Event"). Cyanobacteria such as these would removed carbon dioxide from seawater and released oxygen as a waste product of photosynthesis. It is believed that stromatolites that lived in the Precambrian played a major role in increasing the amount of oxygen in the atmosphere of the primeval Earth ("The Great Oxygenation Event"). Living stromatolites can be found today at Shark Bay in western Australia. The removal of carbon dioxide from the water and the formation of large quantities of calcium carbonate also contributed to the formation of great thicknesses of carbonate rocks in the park.
Blame it on Plate Tectonics . . .
So how did these sea-dwelling organisms end up on a mountaintop in Montana? . . . Blame it on plate tectonics. About 100 million years ago, massive segments of Earth's crust (crustal plates) moved eastward from the area of the Pacific Ocean, pushing into the western edge of North America. This caused the rocks containing the cabbage heads to rise from sea level, forming huge mountains such as those found in this part of Montana. A similar process is happening today in the Himalayas where fossils of ancient sea creatures can be found among the world's highest mountains.
Source: Geology Along Going-to-the-Sun Road, Glacier National Park, Montana, by Omer B. Raup, Robert L, Earhart, James W. Whipple, and Paula E. Carrara: prepared by the USGS in cooperation with the National Park Service, Published by Glacier National Park Historical Association in 1983
Term: carbonate (rock)
CLICK HERE to watch a 2.5 minute video about stromatolites.