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Archived

Avalanche Forecast

Feb 20th, 2024–Feb 21st, 2024
Alpine
1: Low
The avalanche danger rating in the alpine will be low
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
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
Below Threshold
The avalanche danger rating below treeline will be below threshold

The chance of triggering an old wind slab on facets is quite low, but that won't matter if you find the sweet spot! Keep up safe travel practices and the extra caution around ridgelines.

Confidence

Moderate

Avalanche Summary

No new avalanches have been reported, but a large (size 2) natural slab avalanche was reported on Thursday in the alpine. Click on the picture for full details.

Given its solitary appearance amid widespread recent traffic in the White Pass area, this is the kind of avalanche that suggests a quite isolated problem, but one that could be triggered by the weight of a person or machine in a suspect location.

Snowpack Summary

Windblown light new snow amounts are beginning to bury new surface hoar at treeline, but mainly add to variable crusty and wind-affected snow at all elevations and on all aspects. Some softer snow may still be found in sheltered north-facing terrain.

An older layer of surface hoar may be found down 20 - 60 cm in isolated north-facing terrain features. Check out the field team's MIN from Thursday for more.

Below 1500 m, a thick melt-freeze crust is buried 50 - 100 cm deep.

Weather Summary

Tuesday night

Cloudy with scattered flurries bringing 1 - 2 cm of new snow. 40 - 50 km/h southwest alpine wind, increasing. Treeline temperature -5 °C.

Wednesday

Cloudy with isolated flurries, increasing overnight. 45-50 km/h southwest alpine wind, increasing. Treeline temperature -4 °C.

Thursday

Cloudy with continuing flurries bringing 3 - 8 cm of new snow and 3-day snow totals of up to 15 cm, continuing overnight. 60 - 70 km/h south alpine wind, increasing. Treeline temperature -3 °C.

Friday

Cloudy with isolated flurries and another 5-10 cm of new snow from the overnight period. 30-40 km/h southwest alpine wind. Treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully evaluate steep lines for wind slabs.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

Avalanche Problems

Wind Slabs

Elevated winds will begin transporting light new snow and minimal available loose snow into new slabs (likely small). Older, larger wind slabs could prove surprisingly reactive in isolated areas where preserved surface hoar is buried.

Aspects: North, North East, East, North West.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 1.5