Roof was snowboarding recreationally in this backcountry, bowl-shaped run and triggered the avalanche. He was carried nearly 2,000 feet to the base of the mountain and was not successfully rescued. Classification European avalanche risk In Europe, the avalanche risk is widely rated on the following scale, which was adopted in April 1993 to replace the earlier non-standard national schemes. Descriptions were last updated in May 2003 to enhance uniformity. In France, most avalanche deaths occur at risk levels 3 and 4. In Switzerland most occur at levels 2 and 3. It is thought that this may be due to national differences of interpretation when assessing the risks. [1] Stability: Generally described in more detail in the avalanche bulletin (regarding the altitude, aspect, type of terrain etc.) [2] additional load: heavy: two or more skiers or boarders without spacing between them, a single hiker or climber, a grooming machine, avalanche blasting light: a single skier or snowboarder smoothly linking turns and without falling, a group of skiers or snowboarders with a minimum 10 m gap between each person, a single person on snowshoes Gradient: gentle slopes: with an incline below about 30° steep slopes: with an incline over 30° very steep slopes: with an incline over 35° extremely steep slopes: extreme in terms of the incline (over 40°), the terrain profile, proximity of the ridge, smoothness of underlying ground European avalanche size table Avalanche size: North American Avalanche Danger Scale In the United States and Canada, the following avalanche danger scale is used. Descriptors vary depending on country. Avalanche Problems There are nine different types of avalanche problems: Storm slab Wind slab Wet slab avalanches Persistent slab Deep persistent slab Loose dry avalanches Loose wet avalanches Glide avalanches Cornice fall Canadian classification for avalanche size The Canadian classification for avalanche size is based upon the consequences of the avalanche. Half sizes are commonly used. United States classification for avalanche size The size of avalanches are classified using two scales; size relative to destructive force or D-scale and size relative to the avalanche path or R-scale. Both size scales range from 1 to 5 with the D size scale half sizes can be used. Rutschblock Test Slab avalanche hazard analysis can be done using the Rutschblock Test. A 2 m wide block of snow is isolated from the rest of the slope and progressively loaded. The result is a rating of slope