Avalog
Register
Get forecast notifications
Create an account to receive email notifications when forecasts are published.
Register
Login
Archived

Avalanche Forecast

Dec 19th, 2020–Dec 20th, 2020
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
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Northwest Inland.

The snowpack needs a bit of time to adjust to the new snow and wind. Avoid steeper rolls and areas with deeper pillows of wind affected snow. 

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

SATURDAY NIGHT - Flurries, 5 cm possible / west wind, 35-75 km/h / alpine low temperature near -5 

SUNDAY - Sunny with cloudy periods and isolated flurries / west wind, 25-65 km/h / alpine high temperature near -5 

MONDAY - Mainly sunny / light winds / alpine high temperature near -7 

TUESDAY - Cloudy with sunny periods / light winds / freezing levels at valley bottom, but temperature inversion possible

Avalanche Summary

Friday's reports suggest continued snow accumulations are keeping the snowpack near the tipping point. Check out Aaron's MIN here, and this one reporting whumfing (a really important obs about deeper layers). 

Thursday was also an active day. Check out Bryan's great MIN report from Hankin that outlines a few avalanche observations.

Please consider sharing your observations to the Mountain Information Network Thank you to those that have already submitted this winter!

Snowpack Summary

20-40 cm of recent fresh snow and strong southwest wind has formed reactive storm slabs. This new snow sits on an early-December melt-freeze crust with weak and sugary faceted grains around it.

 

A crust that was buried in early November is near the base of the snowpack. This crust has weak facets associated with it. These facets have produced large avalanches in both the south and north of the region. Friday's reports of whumpfs suggest this layer is still a player.

Snowpack depths vary substantially with aspect, elevation, and wind exposure. 

Terrain and Travel

  • Watch for fresh storm slabs building throughout the day.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Avalanche Problems

Storm Slabs

20-40 cm of recent fresh snow with strong southwest winds has likely formed reactive storm slabs. These will probably be very easy to trigger on wind loaded slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1.5 - 2.5

Deep Persistent Slabs

Weak faceted grains near the base of the snowpack have the potential of forming large and destructive avalanches. The most likely place to trigger this layer would be on shallow and rocky slopes. Smaller avalanches may also have the potential of stepping down to this layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3