In order to better understand Avalanches,
it makes sense to first learn about what avalanches are compose of, snow.
Snow forms when atmospheric conditions cause water vapor to condense.
However, it is obvious that all snow doesn't have the same structure.
(Some examples can be seen below)
The density of fresh snowfall is dependent on both
the kind of snow crystal and the air temperature. In cold, calm conditions
the snowfall is the lightest. While in warmer climates, where graupel
and needle crystals fall, the snowfall is the densest. The diagram
below illustrates which structures are formed at different temperatures.
When looking at a cross section of snowfall it is often evident
what weather conditions formed the cross section. This is due to
the different densities and structures of the snow layers. The bonds
between snow layers are large factor in avalanches. If there is a
weak bond between layers, the top layer can easily slide off the bottom
layer. When this happens it is called a slab avalanche. Other
layering characteristic will create other avalanches and hazards, such as
ice avalanches and cornices.