Archived

Avalanche Forecast

Nov 26th, 2014–Nov 27th, 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

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

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.

Stormy, wet, and mild weather (a pineapple express) will maintain high avalanche danger on Thursday. It's best to wait out the storm or stick to simple, low-angle slopes.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Summary: Mild and wet on Wednesday and Thursday following by cool and dry for Friday and into the weekend. Thursday: 15-25 mm Weds night and 30-45 mm on Thursday. The freezing level is near 2000 m. Ridge winds are moderate to strong from the southwest. Friday: Possible lingering flurries. The freezing level drops to around 500 m. Winds ease to light or moderate. Saturday: Mainly sunny. The freezing level is at valley bottom and ridge winds are moderate from the N-NE.

Avalanche Summary

No avalanches have been reported. It's very likely that there was a relatively large natural avalanche cycle early on Wednesday as temperatures spiked and heavy snow turned to rain. Please let us know what you're seeing out there at [email protected].

Snowpack Summary

As we begin our forecasting season, we are working with limited information from the field and base our forecasts primarily off weather station data and forecast weather. In the past 24-48 hours we have seen 40-60 cm of snow fall right down to 1200 m. Early on Wednesday temperatures spiked and it's possible that snow changed to rain all the way up to 2000 m (maybe higher). This recent snow (and rain) may overload a suspected buried weakness (surface hoar, facets and/or a crust) which developed during November's dry spell. This weak layer may be lurking down 60-100 cm. Check the bond of the snowpack at this level and take a cautious approach as new snow builds deeper above this layer.

Avalanche Problems

Storm Slabs

Heavy snow and/or rain could overload buried weaknesses in the mid or lower snowpack. Also, if temperatures cool and snow starts to pile up (instead of rain) a new storm slab could develop.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Loose Wet

Heavy rain could trigger loose wet sluffs in steep open terrain, primarily at and below treeline.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2