Archived

Avalanche Forecast

Mar 28th, 2014–Mar 29th, 2014

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

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: Sea To Sky.

Forecast snow amounts are uncertain. If snow amounts at treeline exceed 20cm, the danger will likely be high there too.

Confidence

Poor - Forecast snowfall amounts are uncertain

Weather Forecast

Synopsis: A broad upper level trough settles in over the Southern Coast which should generate significant precipitation through the weekend. Precipitation amounts have varied wildly from run to run. The amounts shown below are my best guess, but I won't be surprised if the region receives more.Saturday: Freezing Level: 600m rising to 1300 - 1500m Precipitation: 5 -15mm | 5 - 20cm; Treeline Wind: Light, South | Ridgetop Wind: Strong, SouthSunday: Freezing Level: 500m rising to 1200 - 1500m Precipitation: 2-5mm | 2-10cm; Treeline Wind: Moderate, SW | Ridgetop Wind: Strong, SWMonday: Freezing Level: 400m rising to 1400 - 1800m; Precipitation: Trace; Treeline Wind: Light, SE | Ridgetop Wind: Light, SE

Avalanche Summary

No new reports of avalanches.

Snowpack Summary

The recent snow is expected to settle and bond to the mix of old surface crusts and wind slabs with daytime warming and overnight freezing levels dropping down to near valley bottoms. The forecast new snow and strong Southwest winds are expected to develop new storm slabs over the next few days that may release down to the old surface of melt-freeze crusts and/or where facets are sitting on old wind slabs. The added load of storm snow or storm slab avalanches in motion may trigger the March persistent weak layer. The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm.

Avalanche Problems

Storm Slabs

New snow and wind should create fresh slabs that increase in sensitivity to triggering as the day goes on. Slopes immediately lee of ridge crest will likely be the most problematic. The new load may activate the old storm interface too.

Minimize exposure during periods of heavy loading from new snow, wind.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Deep Persistent Slabs

Forecast snow and wind may develop fresh new cornices that could fall off naturally and trigger the deeply buried weak layers. Storm snow avalanches in motion may also trigger these weak layers resulting in very large avalanches.

Be aware of the potential for large, deep avalanches.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Extra caution needed around cornices with current conditions.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 6