Avalanche Forecast

Issued: Apr 21st, 2014 8:38AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.

Avalanche Canada Peter, Avalanche Canada

Resist the urge to rely on danger ratings alone. Conditions change rapidly at this time of year and you need to stay tuned in to local conditions.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tuesday: Cloudy with showers or flurries 10-20 mm or cm depending on elevation. The freezing level is around 2000 m lowering to 1500 m in the evening. Ridge winds are light to moderate from the S-SE. Wednesday: Cloudy with sunny breaks and scattered flurries. The freezing level is around 1500 m and ridge winds are moderate from the SW. Thursday: Mainly cloudy with showers or flurries developing. The freezing level is around 2000 m and winds are light but gusty from the south.

Avalanche Summary

Expect loose wet avalanches in steep terrain if it is raining or during sunny periods, especially if the sun or rain is affecting fresh snow. New storm of wind slabs may develop in higher terrain if we see significant new snow accumulation. Make conservative terrain choices if you see 30 cm of new snow or more in 24-48 hours or significant loading from strong winds. There is still potential for deep persistent slabs to wake up. This is most likely during periods of heavy rain or warm temperatures and strong solar radiation. Your best bet is to pack it in when the snow surface is becoming really wet and mushy.

Snowpack Summary

This is a broad general summary of conditions in the region. This summary is based on very limited field data and should be supplemented with local observations to help assess avalanche danger. Over the past week or so we have seen moderate amounts of moist new snow mixed with showers or periods of rain below 1600-1800 m. Westerly winds have likely formed pockets of wind slab at higher elevations in lee of ridges and terrain features. The upper snowpack generally consists of layers of moist or wet snow mixed with several well bonded crusts. Most areas are likely below threshold for avalanches below 1300-1500 m depending on aspect. The late January/early February persistent weak layer is deeply buried but could still wake up during periods of heavy precipitation (especially rain) or significant warming and solar radiation. Be particularly wary of this on large open alpine slopes. Cornices are large in some areas and should be given a wide berth.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs could develop in exposed lee terrain and cross-loaded slopes near ridge top.
Be alert to conditions that change with elevation.>Be cautious as you transition into wind affected terrain.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

An icon showing Loose Wet
Expect loose wet sluffs in steep terrain during periods of rain, warming, and/or sunshine.
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

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
This problem is unlikely but should remain on the radar. We could see this wake up again with forecast warming, solar radiation and rain.
Use caution on big alpine slopes, especially around thin areas that may propagate to deeper instabilities.>Be aware of the potential for large, deep avalanches due to the presence of buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Apr 22nd, 2014 2:00PM

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