Avalanches

Triple Avalanches on Mt. Index

Every year, 120 to 150 people die in small avalanches in the Alps alone. The vast majority of Alpine victims are reasonably experienced male skiers aged 20–35 but also include ski instructors and guides.[citation needed] However a significant number of climbers are killed in Scottish avalanches often on descent and often triggered by the victims. There is always a lot of pressure to risk a snow crossing. Turning back takes a lot of extra time and effort, supreme leadership, and most importantly there is seldom an avalanche that proves the right decision was made. Making the decision to turn around is especially hard if others are crossing the slope, but any next person could become the trigger.

There are many types of avalanche, but two types are of the most concern. These are Snow Avalanches and Ice Avalanches:

Snow Avalanches

Slab avalanche

This type of avalanche occurs when a plate of snow breaks loose and starts sliding downhill; these are the largest and most dangerous.

Hard slab avalanche

This type of avalanche is formed by hard-packed snow in a cohesive slab. The slab will not break up easily as it slides down the hill, resulting in large blocks tumbling down the mountain.

Soft slab avalanche

This type of avalanche is formed again by a cohesive layer of snow bonded together, the slab tends to break up more easily.

Loose snow avalanche

This type of avalanche is triggered by a small amount of moving snow that accumulates into a big slide. Also known as a "wet slide or point release" avalanche. This type of avalanche is deceptively dangerous as it can still knock a climber or skier off their feet and bury them, or sweep them over a cliff into a terrain trap.

Dangerous slides are most likely to occur on the same slopes preferred by many skiers: long and wide open, few trees or large rocks, 30 to 45 degrees of angle, large load of fresh snow, soon after a big storm, on a slope "lee to the storm". Solar radiation can trigger slides as well. These will typically be a point release or wet slough type of avalanche. The added weight of the wet slide can trigger a slab avalanche. Ninety percent of reported victims are caught in avalanches triggered by themselves or others in their group.


Ice Avalanches are a hazard that exists in glaciated mountain ranges. They are caused by the collapse of unstable ice blocks from a steep or overhanging part of a glacier, referred to as a hanging glacier. Due to the fact that they are part of a glacier, ice avalanches can have large amounts of rock in them. Ice avalanches are quite dangerous because they can travel long distances, sometimes as far as 8 km out onto the glacier valley floor. Ice avalanches are a common everyday occurrence in ranges such as the Alaska Range, Saint Elias Mountains, or Columbia Icefield.

When going off-piste or travelling in alpine terrain, parties are advised to always carry:

1. avalanche beacon
2. probe
3. shovel (retrieving victims with a shovel instead of hands is five times faster)

They are also advised to have had avalanche training. Ironically, expert skiers who have avalanche training make up a large percentage of avalanche fatalities; perhaps because they are the ones more likely to ski in areas prone to avalanches, and certainly because most people do not practice enough with their equipment to be truly fast and efficient rescuers.
Even with proper rescue equipment and training, there is a one-in-five chance of dying if caught in a significant avalanche, and only a 50/50 chance of being found alive if buried more than a few minutes. The best solution is to learn how to avoid risky conditions.