When they're not digging themselves out from under two tons of snow, avalanche scientists use scaled-down models to predict the behavior of snow and ice in a wide range of circumstances. This experiment is a version of those models, using household items to take the place of ice, boulders, snow, and rough terain.

It's best to do this experiment indoors, so that an unexpected gust of wind can't trigger the avalanche before you're ready. You'll be setting up four separate sets of avalanche conditions, arranged as four strips of the same size across the foam board base. If you're being really scientific, you'll have a pen and paper handy to record just what happened--and when--to each of those four.

Materials

• piece of foam board (also called foam-core board) 36 inches by 12 inches
• ruler
• pencil
• wax paper
• scissors
• burlap
• about 10 jelly beans
• glue
• newspaper
• 2 cups granulated sugar
• white flour (5-pound bag)
• 2 cups instant mashed potato flakes
• 4 paperback books of the same thickness

Take Care!

Once you've got all four conditions set up, it's really important to conduct the rest of the experiment slowly and steadily. After all, you're looking for what might be very small movements at first, and you want to be able to note just when each of those occurred. 

What to Do

1. Draw lines dividing the foam-core board into 4 equal parts. First, measure out and mark dots at 9 inches, 18 inches, and 27 inches along the long sides of the board. Then use a pencil to connect those dots so you wind up with 4 panels, each 9 inches wide and 12 inches long. It should look like this:

2. Cut a 9-inch by 12-inch strip of wax paper and an identical strip of burlap. 

3. Glue 4 boulders--er, jelly beans--in a line halfway across the panel on the far left side (that is, roughly 6 inches down). Glue the rest of the jelly beans randomly across the third panel.

4. Glue the wax paper (representing ice) to the second panel and glue the burlap (representing rough terrain) to the fourth panel.

5. Give the glue time to dry. 

6. Spread the newspaper on the table or counter where your avalanche will take place, then put the prepared board on top. It should be level at this point, with the prepared side facing up. 

7. Shake some granulated sugar over the entire board. This represents the first winter snowfall.

8. Sprinkle half of the flour (representing heavy snowfall) over the entire surface, covering the sugar completely, and pat it all down evenly.

9. Now sprinkle a layer of instand mashed potatoes (representing light, dry snow in the coldest part of winter) over everything.

10. Finally, sprinkle the remaining flour (for heavy snow in milder, windier conditions) over everything and pat down evenly.

11. You now have an "avalanche waiting to happen," like Galtur on February 23, 1999.

12. Gently lift one of the long edges of the foam-core board and slide a paperback book under it so that you create a slight slope. Observe any slips and other movement. 

13. Carefully add more books one by one to increase the angle of the slope, noting which conditions are the most (and least) stable.

14. With the tip of your pencil, tap lightly at various points on your slope. Can you spot where the most likely place for an avalanche will be?