|Access path to BEM. Photo Courtesy of SAIS Glencoe|
|Current high avalanche risk and the big avalanche today on BEM made me think a reminder of of the Danger Scale might be worth posting.|
This is the most difficult danger level for back country skiers and boarders to assess snow stability. Many of the usual indicators such as cracks, settling, whumpfing and signs of recent avalanche are absent, especially at the lower end of the moderate level. Key indicators are any recent snowfall, and wind deposition. Snow pack tests may help assess stability.
Conditions are generally favorable for travel providing routes are chosen carefully. The snow pack is only moderately bonded on some steep slopes. Areas of danger are usually restricted to certain types of terrain such as bowls and gullies. The altitude, aspect and type of terrain where danger can be expected are usually detailed in the Avalanche Forecast. Remote triggering is unlikely, so you only need to be concerned about the steepness of nearby terrain features.
Conditions have become much less favorable. The snow pack is only moderately or poorly bonded over a much larger area of the terrain. Human triggering is possible by a single skier on steep slopes and aspects mentioned in the Avalanche Forecast. Remote triggering of avalanches is possible, so the maximum steepness of the slope above you should be used when deciding if you want to continue.
Conditions have become dangerous, most often as a result of significant amounts of new snow, snowfall accompanied by wind or the snow pack becoming isothermal and threatening wet-snow avalanches. The snow pack is poorly bonded over large areas and human triggering is likely on steep slopes (steeper than 30°). Remote triggering is likely and large natural avalanches are to be expected.
|Glencoe 19th March 2013|
Extreme danger levels are rare in Scotland as usually this level is associated with buildings and roads or alpine villages under threat, and usually the result of unusually large amounts of new snow. The snow pack is weakly bonded and unstable. Numerous large avalanches are likely. The weight of the new snow can trigger avalanches on layers buried deep in the snow pack. Natural avalanches can release on slopes of less than 30° Back country touring is not recommended and often impossible. Avoid all avalanche terrain and keep well away from avalanche path run outs.