Triple Divide Peak - Glacier National Park, MT

Like the vast majority of peaks in Glacier Park, Triple Divide is a horn that was beautifully sculpted by glaciers during recent ice ages. These pyramid-shaped peaks are formed as three or more glaciers erode the sides of a single mountain. But, what makes Triple Divide extraordinary is the role it plays in dividing three major watersheds. Runoff from its east side flows into the Gulf of Mexico, the west side flows into the Pacific, and the north into the Hudson Bay. Runoff is melted snow or other forms of precipitation that drain off the land.

You might think a mountain with so much responsibility would tower over the landscape – not so. In fact, Triple Divide is surrounded by taller peaks in every direction. This photo was taken from Norris Mountain, within feet of the Continental Divide (yellow line). “Divides” are simply higher areas (not always distinct ridges or peaks) that separate drainage basins (watersheds). Of course, the Continental Divide (aka “The Great Divide”) is the most famous of all divides. The ridge that runs from Triple Divide to Mt. James in the upper left is another divide – called the Laurentian Divide (red line). It separates the Gulf of Mexico and Hudson Bay watersheds. The faint trail that can be seen descending from the pass between Mt. James and Triple Divide leads down into the Hudson Bay watershed.

The hike to Triple Divide Peak starts at Cut Bank Campground and follows a nice trail to Triple Divide Pass (7.5 miles one-way). From there you must go off-trail to reach the summit. The trip out and back from the campground is a difficult 16 to 17-mile hike with 2,900 ft. of elevation gain. Feel free to download and use any of my photos (see link below).

Related Links
1. Climbing Triple Divide Peak - Includes a Photo Tour
2. Map of the Triple Divide Area - Zoom in or out once the page opens.

Seven days of weather in 13 seconds!

One of the nice things about teaching today compared to when I started in 1982 is the availability of real-time weather-related images and animations. Here's a cool resource provided by the Space Science and Engineering Center at the University of Wisconsin-Madison. It shows 7 days of infrared satellite imagery in a 13-second loop. It moves pretty fast, but you can pause it to point out mid-latitude cyclones, Chinook arches, etc. CLICK HERE to watch it. This page provides several other viewing options, including GOES-East or West, infrared, water vapor, or visible, full-disk or continental US.

Another fun way to show current weather in motion is the WW2010 site provided by the University of Illinois. Once the page open, click on one of the image options, then select animate, choose the number of frames (4-96 hours), and then select "play" or advance the animation one frame at a time.

#133 - Winter Count Recorded Great Meteor Storm of 1833

Above: This is the Medicine Bear Winter Count (photo courtesy of the Montana Historical Society). The winter count is now on display in the new Montana Heritage Center near the Capitol in Helena. Click on it to enlarge.

A communal historical record . . .
Many Plains people recored important events on "winter counts" - hides painted with symbols marking events that happened to a group during the course of a year or "winter". Each year, elders chose the most significant event from the previous year - a battle, a hunt, a natural phenomenon, a death, or a cultural milestone. The winter count keeper would paint a symbol for it on a hide or other material, creating a visual timeline spanning generations. The symbols are arranged in a spiral pattern, usually starting from the outer edge and moving toward the center. The winter count displayed at the Montana Heritage Center, created by a man named Medicine Bear on a deer hide, depicts events experienced by a band of Yanktonai people from 1823-1911. The traditional lands of the Yanktonai (of the Sioux Nation) were between the Missouri and James Rivers in what are now eastern portions of the Dakotas.

The stars fell down . . .
As I was examining at the winter count display at the new museum, I wondered if Medicine Bear had recorded one of the most significant celestial events in recorded history - The Great Meteor Storm of 1833. Fortunately the display has an interactive touch-screen that allowed me to check. As I moved the my finger along the timeline, I stopped at 1833 - and there is was! Like many keepers of winter counts, Medicine Bear had indeed recorded the Great Meteor Storm of 1833. It the most extraordinary meteor shower ever recorded, with an estimated 150,000 to 240,000 meteors per hour streaking across the skies on the night of November 12–13, 1833. People all over North America were awakened by the brightness of the night sky! This event was witnessed and documented by many famous Americans of the time, including Harriet Tubman, Frederick Douglass, and Abraham Lincoln.

Right: A closer look at the symbol Medicine Bear used to depict the Meteor Storm of 1833. Click on it to enlarge.

Comet debris . . .
In addition to causing widespread awe and even fear (many thought it was the end of the world), the storm inspired scientific study, helping astronomers better understand meteor showers. Eventually atronomers determined that the meteor storm of November 1833 was caused by debris from Comet Tempel-Tuttle, which orbits the Sun once every 33 years. Comets, often called "dirty snowballs", are small icy Solar System bodies - Tempel-Tuttle is a little over 2 miles across. As it approaches the Sun, some of the ice changes to vapor, loosening pieces of rock, metal, and dust that were embedded in the ice - so a trail of debris is left behind. Then if Earth passes through this debris as it orbits the Sun, these pieces are pulled toward Earth (gravity), accelerating to incredible speeds. As they enter the atmosphere, the friction generates heat and light as the pieces vaporize. Most are particles the size of a grain of sand or a pea that burn up (vaporize) completely. Larger, brighter meteors (fireballs) are produced by objects from the size of a fist to a car, but even most these often disintegrate before reaching the ground. Pieces that do reach Earth's surface are called meteorites.

Meteor Showers . . .
There are several meteor showers on known dates every year. All are caused by Earth passing through debris left behind by certain comets. For example the Perseid meteor shower which peaks around August 12-13 is caused by Earth passing through debris from Comet Swift-Tuttle. Swift-Tuttle is about 16 miles across and orbits the Sun once every 133 years. Meteor showers can have dozens of meteors per hour, whereas meteor storms can have over 1,000 meteors per hour, often occurring when Earth hits a particularly dense fresh stream of debris from a comet.

Term: Leonid Meteor Shower

CLICK HERE to learn much more about the Medicine Bear Winter Count, inlcuding short descriptions of what each of the 80+ symbols mean. For example 1837 and 1838 were small pox years, and 1911 was the year many of the children got measels.

CLICK HERE to learn much more about the annual Leonid Meteor Shower, including the Meteor Storm of 1833.

A picture is worth a thousand words . . .

It is very important that students understand how water drains off the land to form streams and rivers that eventually (usually) flow to the ocean. Images like this will definitely help. CLICK HERE to see several other images and an impressive animation, created by Imgur user Fejetlenfej,a geographer and GIS analyst.

A map such as the one shown above can be very effective in helping explain the concept of watersheds (and divides). Click on the map to enlarge - and appreciate the detail. It might also serve as the focus of a "bell-ringer". For example, have students write out 3 quality questions about the map - stipulating that each question must begin with the word "why". Then in your discussion of the bell-ringer, ask if they would be able to use the map to mark the location of the Continental Divide (aka the Great Divide).

Great 15-second video of a microburst!

If you know of a better video of a microburst, let me know. This one is great! For more about microbursts CLICK HERE.

8-30-15 - Wet Microburst Chandler Arizona from Monsoon Tracker on Vimeo.

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#136 - Snake Butte Boulder Train

Say cheese! . . .
This photo was taken along Highway #66 south of the Ft. Belknap Agency near mile marker 36. The cows are posing by pieces of Snake Butte that were carried here by the Laurentide Ice Sheet. That is Snake Butte in the background, ~8 miles away. The boulders are part of the "Snake Butte Boulder Train" - pieces of the butte that have been scattered in a 1-2 mile wide swath extending to the southeast of Snake Butte for about 50 miles. In places the pieces of Snake Butte are few and far between, but many of them are very big like the those shown in the photo. The best place to see rocks of the boulder train is on the west side of the highway between mile markers 35 and 36.

I'm melting! . . .
During the last two glaciations (commonly called ice ages), the Laurentide Ice Sheet grew southward into Montana but the Bears Paw Mountains turned it toward the southeast as it grew into this area. The pieces of igneous rock that the butte is made of were plucked away from the butte as the ice flowed over it. They were transported by the glacier(s) as it continued to flow - Then as the ice age(s) ended the glaciers melted, dropping the rocks where they sit today.

Right: The map is from the new edition of Roadside Geology of Montana, Hyndman and Thomas, 2020 - Great Resource! Click on the map to enlarge.

Standing out . . .
Rocks transported away from the place where they formed by glaciers are called "erratics". There are MANY glacial erratics along the Hi-Line and beyond that originated in northern Canada where the Laurentide Ice Sheet started growing from. However, Snake Butte is made of a unique kind of igneous rock called Shonkinite - so its erratics are very easy to recognize among the others scattered throughout the area.

Term: Laurentide Ice Sheet

Below: Here are some big pieces of Snake Butte. In some places they are few and far between - in other parts of the boulder train there are many in one place. One location where they are abundant is on the west side of Highway #66 near mile marker 35.

#122 - Shonkin Sag Laccolith - Born of Fire and Ice

Do you think Charlie knew?
Fifty million years before Charlie Russell painted scenes of central Montana, a volcano dominated the landscape east of Great Falls - The Highwood Mountains are the eroded remains of this ancient volcano. The chamber that provided the magma for these features is also responsible for the dark cliff shown in the photos on this page. Pressure from magma beneath volcanoes can cause surrounding bedrock to crack, and then magma moves into the cracks or between layers of sedimentary rock, hardening beneath the surface. If a magma-filled fissure cuts across layers of sedimentary rock, the formation is called a dike. If magma forces its way between layers of rock, it is called a sill. If enough moves in to cause layers above to dome up, the formation is referred to as a laccolith. Square Butte and Round Butte are both laccoliths, and so is the cliff shown above. Stay tuned for more about this famous cut bank later.

Does anyone feel a chill?
Fast-forward to 2.6 million years ago (mya) . . . The Highwood Volcano had gone extinct, and erosion had taken it's toll on the cone(s) and the sedimentary layers that the dikes and laccoliths were embedded in, exposing some as ridges and buttes. Also, by around 2.6 mya, the planet had cooled enough for another ice age to get started. From 2.6 mya until 12,000 years ago, Earth experienced several glaciations (commonly called "ice ages"). Over tens of thousands of years, great ice sheets grew southward from Canada into the northern Montana. Then those glaciers would melt, replaced by warmer "interglacial periods" that would last for thousands of years before next glacial period started. Over the past 1 million years these glacial periods occurred roughly once every 100,000 years. The most recent one ended 12,000 years ago, marking the end of the Pleistocene epoch.

Here comes that dam glacier!
The formation and flooding of Glacial Lake Missoula (multiple times) is one of the most famous events that occurred during the most recent glaciation. However, a lesser-known incident that shaped the cliff shown in the photos on this page was also quite dramatic. Here is one hypothesis** . . . The strange set pf circumstances began when the Laurentide Ice Sheet grew southward from Canada, reaching the north slopes of the Highwood Mountains. As the ice sheet pinched against the Highwoods, it blocked the flow of the ancient Missouri River, causing the formation of Glacial Lake Great Falls. At times the lake was about 500 feet deep where the courthouse sits in Great Falls today, and lake water backed up as far south as the Helena Valley.

The big spill.
The lake eventually grew high enough to spill over the dam near the present-day town of Highwood. At some point the ice dam burst, and water rushed along the southern edge of the ice sheet (along the north side of Highwoods) across existing drainages, carving the impressive channel known today as the Shonkin Sag. Eventually the ice grew back, the lake refilled, and the dam burst again - probably numerous times. Today the wide, deep, dry channel with scattered brackish lakes winds its way between the small towns of Highwood and Square Butte.

Not so fast!
Gerald Davidson, a retired research scientist who spent years studying the area, agrees that outburst floods are part of the story, but thinks the area's unique landscape was shaped by a more complicated sequence of events that happened over a longer span of time. According to Davidson, "For the past million years the Earth has spent most of the time locked in ice; so there has been sufficient time for a river to gradually cut a channel around the ice - a channel that could have been scoured and enlarged by several violent overflow events."

Above: Photo by Mark Smith - a closer look at the cliffs of the Shonkin Sag Laccolith

That's some cut bank!
For geologists who visit this remote area to see the Shonkin Sag, the cliff shown in the photos on this page is a "must see". Here, two very different events, separated by tens of millions of years - a period of volcanism and an ice age, teamed up to provide this unique cut bank. This is where ice age torrents of water in the Shonkin Sag cut into the Shonkin Sag Laccolith, exposing the spectacular cross-section represented by the cliff. Such views of plutonic formations are rare - something normally only seen in textbook diagrams. In the photo above, the thick dark part toward the left is eastern edge of the laccolith, and the dark stripes on the right are sills formed as magma from the laccolith squeezed between layers of sandstone. The photo below, which was taken from the top of Square Butte (4-5 miles away), provides a much different perspective. The laccolith is about 200 feet thick and a mile long.

Below: Cliffs of the same Shonkin Sag Laccolith - photo taken from top of Square Butte

Term: outburst flood

*Note: The use of the term "ice age" is confusing. For more about this, click here.

Blog and Photos from Hike to Shonkin Sag in April 2016