The European avalanche warning services divide avalanches into five size categories (based on the Canadian classification). The avalanche size is defined, among other things, by the potential damage caused.
Under this definition, fatal 'skier-triggered avalanches' are often classified as 'medium' or (barely) as 'large' avalanches and reaches considerable dimensions, being typically 150 m in length and having a slab size of some 50 m by 80 m and an average slab thickness of around 50 cm. This is equivalent to a slab volume of approximately 2000 m3 or around 400 tonnes.
Unlikely to bury a person, except in unfavourable runout zones
In extreme terrain there is a danger of falling.
Stops on a steep slope
Length: 10 – 30 m
Volume: 100 m3
Can bury, injure or kill people
Many avalanches that kill people are classified as 'medium'.
Can reach the end of the relevant slope
Length: 50 – 200 m
Volume: 1000 m3
Can bury and destroy cars, damage trucks, destroy small buildings and break a few trees
Many avalanches that kill people are classified as 'large'.
Can cross flat terrain (well below 30°) over a distance of less than 50 m
Length: Several hundred metres
Volume: 10,000 m3
Can bury and destroy trucks and trains Can destroy fairly large buildings and small areas of forest. Very large avalanches can occur at danger level 3 and are typical of danger levels 4 and 5.
Traverses flat terrain (well below 30°) over a distance of more than 50 m
Can reach the valley floor
Length: 1 – 2 km
Volume: 100,000 m3
Can devastate the landscape and has catastrophic destructive potential
Typical for danger level 5
Reaches the valley floor
Largest known avalanche
Length: Approx. 3 km
Volume: > 100,000 m3