Lecture 6 - Avalanches

Question 1

Snow avalanche?

Answer 1

Masses of snow that separate from the intact snowpack and slide or flow downslope

Question 2

What are the sizes of avalanches?

Answer 2

Sluff (smallest)
Small
Medium
Large

Question 3

On which slopes does snow accumulate the best?

Answer 3

Those with angles less than 45º

Question 4

Point-release avalanches?

Answer 4

failure of a small amount of loose fluffy snow

Question 5

Slab avalanches?

Answer 5

snowpack fractures along a weak layer at depth, moves as a cohesive block

Question 6

Wind slab?

Answer 6

Thick poorly bonded snow deposited by wind

Question 7

Hoar?

Answer 7

ice crystals deposited on snow when air is moist and cold

- layers of hoar generally have lower strength than the rest of the snowpack

Question 8

Start zone?

Answer 8

Where the snowpack fails

Question 9

Track?

Answer 9

Path of accelerationand velocity

Question 10

Run-out zone?

Answer 10

deceleration and deposition

Question 11

Avalanches tend to occur on slopes with which angles?

Answer 11

25-69º

Question 12

What kind of slopes are more dangerous?

Answer 12

Convex slopes are more dangerous than concave

Question 13

If rescued within 15 minutes, what are your chances of survival?

Answer 13

92%

Question 14

If buried in more than 1.5m of snow, what are your chances of survival?

Answer 14

5-10%