Heavy snowfall and strong wind are creating very dangerous avalanche conditions. Avoid avalanche terrain, and stick to simple, low-angle slopes with no overhead hazard.
25-60 cm of new snow is forecast to accumulate by Saturday afternoon, with higher totals expected in areas southwest in the region. The new snow will likely form a widespread, touchy storm slab problem across elevations and aspects. Winds are forecast to be strong to extreme from the southwest. Anticipate larger, more reactive slabs in wind-drifted areas.
Natural avalanches releasing in the new snow are likely on Saturday. These storm slab avalanches are expected to be large, widespread, and very sensitive to human triggers.
Heavy snow and strong wind on Saturday
Friday night: Overcast, 10-30 cm of snow above 900 m, areas southwest in the region could see 40 cm of snow above 1500 m, extreme southwest winds, treeline temperatures rising overnight to -1 C, freezing level rising to 900 m.
Saturday: Overcast, another 10-30 cm of snow above 700 m, areas southwest in the region could see 40 cm of snow above 1300 m, strong southwest winds, treeline temperatures cooling from -1 C to -4 C, freezing level dropping to 500 m.
Sunday: Partly cloudy, up to 5 cm of snow, winds becoming east and light, high treeline temperatures near -3 C, freezing level around 700 m.
Monday: Mainly sunny, no precipitation expected, light southeast winds, high treeline temperatures near-2 C, freezing level around 300 m.
An intense storm is taking aim at the region, with 25-60 cm of new snow expected by Saturday afternoon. A strong storm is taking aim at the region, bringing strong southwest winds and 25-60 cm of new snow by Saturday afternoon. During the heaviest snowfall mid-morning on Saturday, freezing levels are forecast to rise to around 900 m, creating denser snow over lighter snow and potentially forming a mid-storm crust layer. Higher snow totals and freezing levels may be found in southwest parts of the region. Periods of extreme southwest wind will likely be a major contributor to the size and likelihood of Saturday's storm slab problem. Even steep opening in the trees should be treated as suspect on Saturday.
Below up to a meter of snow from the past week, two crust layers can be found that formed in early December. Small facets (sugary snow) have been reported near these crusts that may transition into a persistent slab problem. Recent snowpack tests have demonstrated instability at this interface, though with limited propagation potential. This layer could have potential to be triggered in shallow, rocky zones near ridge tops, where the facets are more developed and where the crust layers are more accessible to the weight of a person or machine. Check out this MIN report from the Elk Mountain area on Tuesday.
Below these crust layers, the snowpack is generally well-settled. Early season hazards such as rocks, stumps, and open creeks remain at lower elevations.
