The snowpack shakedown has begun. Set your exposure to avalanche terrain and overhead hazard to the minimum during the warmup. It might feel like spring, but the snowpack is far from settled.
Strong southwest winds redistributed much of our loose surface snow into wind slabs in the lee of exposed terrain features on Wednesday. Wind slab releases could step down to a buried weak layer to create a much larger avalanche.
A 40 - 60 cm-deep weak layer of large facets produced avalanche activity during the recent storm. Forecast warming will promote natural activity and human triggering potential.
Solar warming will work to destabilize snow on sun-exposed slopes sheltered from wind. Wet snow may shed naturally or with a human trigger. Loose snow releases may trigger destructive slab avalanches.
Two size 2 wind slabs were targeted with explosives on Wednesday in the Castle area. They featured 10 - 30 cm crowns that were noted for containing three distinct wind slab layers from recent loading events.
On Monday, explosives control in the same area produced avalanches to size 2 on east/southeast facing slopes. These involved both storm snow and the buried late-January weak layer, which is expected to remain reactive during the ongoing warmup.
A melt-freeze crust moist or snow now glazes the surface on solar aspects and, by Friday, below about 2100 m. The depth of affected snow should increase over the coming days and crust recovery may be weak. This process will affect around 30 cm of settling recent snow, which has been redistributed by strong southwest winds at treeline and above.
The main feature of the region's overall shallow snowpack is a persistent weak layer of surface hoar or facets from late January now buried 40 to 60 cm deep (see photo below). This layer is expected to be increasingly reactive as warming tests the snowpack.
Check out this MIN for recent conditions in the Elkford area.
Thursday Night
Becoming cloudy. 15 to 20 km/h west ridgetop wind, easing. Freezing level falling from 2000 m to 1600 m.
Friday
Mostly sunny. 15 to 20 km/h west ridgetop winds, easing. Freezing level to 2400 m. Treeline temperature 5 °C.
Saturday
Sunny. 20 to 25 km/h west ridgetop wind. Freezing level to 3000 m, rising overnight. Treeline temperature 6 °C.
Sunday
Sunny. 5 to 10 km/h west ridgetop wind. Freezing level 3200 m - 2800 m. Treeline temperature 7 °C.
More details can be found in the Mountain Weather Forecast.
