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Saturday, December 31, 2016

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.

Tuesday, December 27, 2016

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.

Saturday, December 17, 2016

'Tis the Week to Explain the Solstice

The Winter Solstice will occur at 3:44 am MST on Wednesday, December 21. It always amazes me at how many adults do not understand the cause of the seasons, or why the length of day varies throughout the year. A significant percentage think that the seasons are caused by Earth being closer to the Sun in the summer, and farther in the winter. Actually, Earth is closest to the Sun in early January and farthest in early July! As for the length of day, I think many do connect it with Earth's tilt, but few can really explain the dynamics. Try this sometime this week . . . Give your students a few minutes at the start of class to answer two questions on a slip of paper. Have them hand them in, and then use the resources below to explain the answers.

1. What causes Earth to experience seasons?

2. Why is the length of daylight longer in the summer and shorter in the winter?

CLICK HERE to see an animation courtesy of the Santa Barbara City College Dept. of Physics and Engineering. I project the animation onto a big screen and use it to explain the solstice (and its relationship to the length of daylight). CLICK HERE for more information about the solstice. CLICK HERE to see another animation (courtesy of Prentice Hall). CLICK HERE to get sunrise and sunset times for your city.

CAUTION: Animations and diagrams often depict the shape of Earth's orbit as being more elliptical than it really is. If you were to draw our orbit on the board, it would look like a circle. Here is another resource that may help. Once the page open, the diagram titled "Eccentricity" is a good one. This Hours Explorer is pretty slick too! (Thanks, Rick)

Merry Christmas!

Thursday, December 15, 2016

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).

Friday, December 9, 2016

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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Sunday, December 4, 2016

Refraction Caused by a Temperature Inversion

This photo (courtesy of bigskywalker.com) was taken from the Continental Divide trail, about 30 miles northwest of Helena, MT. The valleys were in the midst of a foggy temperature inversion, and a Fata Morgana (superior mirage) was present over the distant mountains. “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 - the strange shapes in the photo are the result of light waves from distant mountains being refracted as they traveled through layers of various temperatures (diagram). Apparently the temperature inversion that blanketed the area was one of the factors that allowed the sorceress to do her handiwork. For more about this hike (including many more photos), go to bigskywalker.com.

Wednesday, May 4, 2016

Shonkin Sag Laccolith - Born of Fire and Ice

This cliff in central Montana was formed by two very different events separated by tens of millions of years - a period of volcanism and an ice age. Here, ice age flows of water along the southern margin of the Laurentide Ice Sheet 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. To learn more click here (site does not open on many mobile devices).