Geology Reference
In-Depth Information
FIGURE 8.22
Aerial photo (1976) of apartment site.
PART D. THE NATURE AND OCCURRENCE
OF SNOW AVALANCHES
There are two principal types of snow avalanches:
loose snow avalanches and slab avalanches. These types
are illustrated in Figure 8.24. Loose snow avalanches
start at a point or over a small area. They grow in size
and the quantity of snow involved increases as they
descend. Loose snow moves as a formless mass with lit-
tle internal cohesion. Slab avalanches, on the other hand,
start when a large area of snow begins to slide as a mass.
The goals of part of the exercise are to familiarize you
with some of the basic causes of avalanches and intro-
duce you to various types of avalanche terrain.
The following text is slightly edited from the U.S.
Forest Service brochure "Snow avalanche: General rules
for avoiding and surviving snow avalanches."
