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RegisterFeb 1st, 2020–Feb 2nd, 2020
South Columbia.
While refrozen surfaces at lower elevations pose little avalanche hazard, large avalanches may be triggered in areas with wind-drifted snow at higher elevations. Be prepared to assess conditions and adjust your travel as you gain elevation.
Saturday night: Decreasing cloud, scattered flurries with 2-5 cm of snow, moderate west winds, alpine temperature -10 C.
Sunday: Mostly clear, light southwest winds, alpine high temperatures around -5 C.
Monday: Cloudy with periods of sun, light northwest winds, alpine high temperature -7 C.
Tuesday: Increasing cloud, light southwest winds, alpine high temperature -8 C.
During the storm, numerous large, natural (size 2-2.5) storm and wind slab avalanches were reported in the region. These avalanches occurred primarily on leeward aspects (northwest, northeast, east) and mainly at treeline and alpine elevations. Reports also indicate that cornices may be reaching their breaking point and may act as triggers for these avalanches. Below tree line, small wet loose avalanches were releasing naturally on Saturday.
Over the last week, there have been two notable natural avalanches reported in the south of the region. These were large (size 2.5) avalanches breaking 200 cm deep on both northeast and northwest slopes above 2300 m. Although unlikely, these avalanches are a reminder that a deeper instability may linger in isolated areas where the snowpack transitions from thick to thin. Easier-to-trigger storm slab avalanches or cornice fall may have the potential to step-down to this layer.
Snow accumulation varied widely across the region, with higher amounts falling in the eastern half. Anywhere from 20-60+ cm of storm snow has accumulated at upper elevations (generally above 1900 m). Strong southwest winds have drifted the snow into deeper, stiffer slabs in wind-exposed areas and have rapidly loaded cornices. During a warming event Saturday night, rain saturated snow surfaces up to around 1900 m that have since refrozen with cooling temperatures.
The mid and lower snowpack is generally well settled and strong. Although isolated, there are two deeper layers that may still persist. A layer surface hoar currently buried 90 to 170 cm deep from late December and a facet/crust layer from November near the ground.