Snow Avalanches

Alessandro Zanazzi
Utah Valley University, Earth Science
Author Profile


In this activity, students have to select the most convenient backcountry ski route to climb a peak located near Brighton ski resort (Utah). In order to select the route, they have to evaluate the information provided by the Utah Avalanche Center and to calculate distances and slope angles from a topographic map of the area.

Used this activity? Share your experiences and modifications

Learning Goals

Students will learn to calculate slope angles and distances from a topographic map. They will learn to think critically in order to select the safest route.

Context for Use

This is a classroom activity that follows a lecture on snow avalanches. It takes 30-45 minutes. I have used it in lower division geology courses of 40-60 students at a 4 year teaching institution, but I think it can be used in classes of any size and in other settings. I usually hand out a real topographic map of the area (pdf file attached). The technical skills required are reading topographic maps, calculating distances, and slope angles. Students need to know the formula for calculating slope angles (i.e., angle=tan-1(rise/run) and some basic information about snow avalanches.

Description and Teaching Materials

This activity is very simple to adopt. I usually hand out a real topographic map (Brighton Quadrange; pdf attached) but, strictly speaking, it is not necessary. Students can use the part of the map that I have inserted in the last page.
Activity Handout (Microsoft Word 2007 (.docx) 7.8MB Apr30 19)
Brighton Quadrange Topo Map (Acrobat (PDF) 20.2MB Apr30 19)

Teaching Notes and Tips

Students usually have a hard time to understand how to calculate topographic gradients. I repeat how to apply the formula several times during the semester when I cover different topics (topographic maps, landslides, groundwater). They also struggle in unit conversions. It is probably a good idea to point them to "The Math You Need When You Need It".


I informally assess their learning by walking around and observe their work while they complete the activity. I also include a few questions on how to calculate distances and topographic gradients in the exams that follows the activity.

References and Resources

Here's the link to the website of the Utah Avalanche Center with the forecasts for different areas:

Here's the link to the Math You Need When You Need It: