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Avalanche Forecast

Mar 29th, 2018–Mar 30th, 2018
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Northwest Inland.

New snow fell in the south of the region. Expect to find loose dry snow in sheltered areas and storm slabs in exposed areas. New and old slabs aren't bonding well to underlying layers. Conservative decision-making is recommended.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

THURSDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm, moderate southwesterly winds, alpine temperature -7 C, freezing level 700 m.FRIDAY: Mostly cloudy with trace snowfall, light southeasterly winds, alpine temperature -10 C, freezing level 500 m.SATURDAY: Mostly cloudy with trace snowfall, light southerly winds, alpine temperature -9 C, freezing level 600 m.SUNDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, light southwesterly winds, alpine temperature -9 C, freezing level 600 m.

Avalanche Summary

Evidence of a widespread avalanche cycle was observed on Wednesday and Thursday. Large to very large (size 3 to 4) storm slabs were observed, often in southeast, east, and northeast slopes. Some of these stepped down to weak and sugary facets at the bottom of the snowpack.

Snowpack Summary

Thursdays storm is expected to bring another 10 to 30 cm of snow to the southern parts of the region. This overlies last weekends 40 cm of storm snow, which has settled into a reactive slab and is not bonding well to old snow surfaces. These include two layers of surface hoar, which exist on shaded aspects at high elevations as well as a melt-freeze crust on all aspects at treeline and below treeline elevations.Deeper in the snowpack, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist from mid- and late-February and a surface hoar/crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, weak and sugary facets exist, particularly in steep, rocky, and shallow snowpack areas. Shallower storm slabs have stepped down to these facets recently, producing very large avalanches.

Avalanche Problems

Storm Slabs

Slabs are not bonding well to underlying layers, including surface hoar, a crust, or sugary facets in thin snowpack areas. Very large avalanches have occurred. Observe for signs of instability, such as cracking, whumpfing, and avalanche activity.
Approach lee and cross-loaded slopes with caution.Be aware of the potential for loose dry avalanches in steep terrain where snow hasn't formed a slab.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1.5 - 3.5