Avalanche Forecast

SUNDAY Night: Clear periods, light southwest wind, alpine temperature -8 C.

MONDAY: Clear skies, light west wind, alpine temperature -5 C, freezing level 1000 m.

TUESDAY: Cloudy with scattered flurries, moderate southwest wind, alpine temperature -4 C, freezing level 1200 m.

WEDNESDAY: Cloudy with scattered flurries, moderate to strong southwest wind, alpine temperature -5 C, freezing level 1100 m.

On Sunday there was skier triggered size 2 persistent slab avalanche in the north of the region that is suspected to have run on weak facets that were buried in late November. It was on a northwest aspect at 2200 m and may have been a slope that had slid previously and was reloaded.

On Friday, explosives triggered cornices and 20 cm slabs within the recent storm snow, producing small (size 1 to 1.5) up to large (size 2) avalanches. The avalanches were on west to north aspects and at alpine elevations. A persistent slab avalanche was triggered by a rider in the northern part of the region, likely releasing on the surface hoar layer described in the Snowpack Summary. The avalanche was large (size 2), in alpine terrain, and on a northerly aspect.

15 to 25 cm falling late last week with strong south to southwest wind has formed wind slabs in lee terrain features at treeline and alpine elevations.

A weak layer of surface hoar crystals and/or faceted grains may be found around 40 to 80 cm deep on northerly aspects at treeline and lower alpine elevations. The layer may have been destroyed by strong wind immediately before burial on February 22nd, but it may still exist in sheltered terrain features. Where it exists, it has been reactive in some snowpack tests but not others, suggesting spatial variation. This persistent weak layer warrants investigation and a conservative terrain use strategy. Check out the latest forecaster blog that offers a deeper dive into these conditions.

In the northern part of the region (i.e., Duffey/Hurley/Goldbridge), a deep instability may linger at the base of the snowpack. It has not produced an avalanche since February 17th. Human-triggering is unlikely, though if one were to trigger the layer, it would likely be in a thin, shallow, rocky spot. A large load, such as from a cornice fall, or rapidly changing weather have the potential to trigger this layer.

• Carefully evaluate steep lines for wind slabs.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Minimize exposure to sun-exposed slopes when the solar radiation is strong.
• Surface hoar distribution is highly variable. Avoid generalizing your observations.