Avalanche Forecast

THURSDAY NIGHT: Cloudy with snowfall, accumulation 10 to 15 cm in the south of the region and 2 to 5 cm in the north, moderate southwest wind, alpine temperature -10 C.

FRIDAY: Mix of sun and cloud, light southwest wind, alpine temperature -10 C, freezing level 1000 m.

SATURDAY: Mix of sun and cloud with isolated flurries, light southwest wind, alpine temperature -10 C, freezing level 800 m.

SUNDAY: Early-morning snowfall then mix of sun and cloud, accumulation 2 to 5 cm, light west wind, alpine temperature -10 C, freezing level 900 m.

A few small (size 1) wind slabs were triggered in the region on Wednesday. They released naturally and by humans. 

Although we do not have reports yet of avalanche activity from Thursday, it is suspected that many storm and wind slab avalanches were triggered naturally and by humans within the new storm snow. Natural avalanche activity should decrease on Friday, with the exception of sun-exposed slopes during intense sunny conditions. Human-triggering of avalanches may remain likely on Friday.

Thursday's storm dropped around 15 to 25 cm of snow across the region. The snow fell with strong south to southwest wind, forming 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 exists 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.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Continue to make conservative terrain choices while the storm snow settles and stabilizes.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• Surface hoar distribution is highly variable. Avoid generalizing your observations.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.