Avalog Join
Archived

Avalanche Forecast

Jan 23rd, 2015–Jan 24th, 2015
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
4: High
The avalanche danger rating below treeline will be high
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
4: High
The avalanche danger rating below treeline will be high
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

The wet, warm, and windy storm will result in High avalanche danger.

Confidence

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

Weather Forecast

Heavy snow or rain below 1600 metres is expected to continue on Friday night. There may be a short break between storms Saturday morning, before the next 30-40 mm of precipitation combined with very strong Southwest winds and freezing levels up to about 2200 metres moves into the region. Expect another 10-15 mm of precipitation with moderate to strong Southwest winds on Sunday as freezing levels creep below 1500 metres. Monday should be drier with periods of flurries or showers, moderate winds, and freezing levels dropping below 1000 metres.

Avalanche Summary

Very heavy loading from snow, wind, and rain has resulted in a widespread natural avalanche cycle up to size 4.0 on Thursday. Reports from Wednesday include numerous wind slab and some step-down persistent slab avalanches in the Size 2-3 range, with isolated deep persistent slab avalanches up to size 3.5 from large alpine features. Below approximately 1000m numerous wet loose snow avalanches up to Size 2.5 were observed running in steep terrain. This pattern should continue throughout the forecast period.

Snowpack Summary

Heavy snowfall (with rain below approximately 1500-1000 m) and strong southwest winds have built fresh deep and dense storm and wind slabs. The slabs are likely 'upside down' with warm temperatures dropping moist dense snow on previous dry lower-density snow. A rain crust and/or surface hoar layer buried mid-December is down around a metre. Recent reports mention that this weakness has become 'electric' with recent heavy loading and has been responsible for much of the recent large avalanche activity. The November crust near the bottom of the snowpack is generally well bonded, but may 'wake up' with intense loading this week. There is potential for isolated very large and deep avalanches.

Avalanche Problems

Storm Slabs

Heavy loading from snow and wind is expected to maintain widespread natural avalanche activity at and above treeline, especially on wind loaded slopes (N to E facing).
Be alert to conditions that change with elevation.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 2 - 6

Wet Slabs

Expect wet avalanche activity in all steep terrain below treeline. Beware of gaping glide cracks.
Avoid slopes with glide cracks.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 1 - 5