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Avalanche Forecast

Jan 20th, 2020–Jan 21st, 2020
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
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: South Coast.

Conditions will vary with elevation on Tuesday as the freezing level drops and rain transitions into snow.

Confidence

Moderate - Uncertainty is due to difficult to forecast freezing levels.

Weather Forecast

MONDAY NIGHT: Cloudy with light rain, moderate wind from the south, treeline temperatures around +2 C.

TUESDAY: Rain transitioning to snow as freezing level drops from 1500 to 1000 m, accumulations of 20-40 cm of new snow above 1000 m, strong wind from the south, treeline temperatures around 0 C.

WEDNESDAY: Flurries continue with 10-15 cm of snow above 1000 m, moderate wind from the south, treeline temperatures around 0 C.

THURSDAY: Heavy rain up to 1800 m (40-70 mm), strong wind from the southwest, treeline temperatures around +5 C.

Avalanche Summary

Before snow turned to rain on Monday a few small (size 1) storm slabs were reactive to skiers and explosive triggering on steep features over the weekend. See this MIN report for an example.

Snowpack Summary

20-40 cm of new snow by Tuesday evening will bury wet and crusty snow left over from the rain on Monday. While it snowed a whopping 100-170 cm last week, this snow has since been soaked by heavy rain all the way to the tops of the North Shore mountains. In higher elevation peaks there may still be dry snow and potential wind slab or storm slabs problems.

Terrain and Travel

  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
  • Remember that the snowpack will be significantly different at higher elevations than lower down.

Avalanche Problems

Storm Slabs

Fresh storm slabs are expected to build on Tuesday, with depth and reactivity that increases with elevation and exposure to wind. Switch your mindset to managing wet loose avalanches if you find rain accumulating at treeline instead of new snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2