Avalog Join
Archived

Avalanche Forecast

Feb 18th, 2014–Feb 19th, 2014
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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: Sea To Sky.

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

The next Pacific frontal system will cross the South Coast on today resulting in strong wind and precipitation. Generally unsettled conditions are expected for Wednesday before another weak system affects the region Wednesday night or Thursday morning.Tuesday night:  Freezing levels at valley bottom. Precipitation, 5 to 10 cm, ridge top winds 40-60 Km/h  from the W.Wednesday: Freezing levels at valley bottom, trace of precipitation, ridge top winds 20-30 Km/h from the W.Thursday: Freezing level at valley bottom, 5 to 10cm of precipitation, ridge top winds  50-90 Km/h from the W.Friday:  Freezing level at valley bottom, no precipitation in the forecast, winds light, gusting to occasional 40 Km/h.

Avalanche Summary

We're still seeing reports of large natural and explosive triggered avalanches throughout the forecast region. All are storm slab avalanches and occurred on all aspects and all elevation bands. Most running on the Feb. 10th facet/crust/surface hoar combo.

Snowpack Summary

Recent snowfall amounts exceed 1.75m during the past week and has now settled into a storm slab with a typical thickness of 60-100cm. The storm slab is overlying a variety of old weak surfaces that developed during the past cold,dry spell. It consists of weak facets, surface hoar, a scoured crust, wind pressed snow, or any combination of these. A poor bond exists between the storm slab and these old surfaces.Of particular concern is the combination of buried facets on a crust being unusually reactive at tree line and below. Avalanche activity, whumpfing and snowpack tests at these elevations are showing easy sudden planar shear results on the facet/crust combo. Strong to extreme winds are redistributing the new snow into deeper, and denser wind slabs on lee slopes.The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region, but triggering has become unlikely.

Avalanche Problems

Storm Slabs

An abundance of new snow has built a very touchy storm slab that is reactive at all elevation bands. A poor bond on a variety of old weak interfaces creates the perfect recipe for dangerous avalanche conditions. Thick wind slabs exist on lee slopes.
Use caution in lee areas in the alpine and treeline. Recent wind loading have created wind slabs.>Stick to simple terrain and be aware of what is above you at all times.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 2 - 5