Avalanche Forecast

Issued: Apr 24th, 2014 9:06AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs, Cornices and Deep Persistent Slabs.

Peter, Avalanche Canada

South Rockies.

We are no longer issuing danger ratings for this region due to a lack of field data.Check out this video and blog post for more insight into managing spring conditions.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: The weather pattern should remain cool and unsettled through the weekend. Expect periods of light to moderate precipitation mixed with sunny breaks most days. The greatest amount of precipitation should be on Saturday (5-10 mm or cm). Freezing levels should climb to 1800-2000 m each day and rebound to around 1500 m overnight. Ridgetop winds are generally light to moderate from the southwest.

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 solely on recent weather data and previous snowpack information. It should be supplemented with local observations to help assess avalanche danger.Over the past week we have seen light precipitation with a snow line somewhere around 1800 m (+/- 200 m). This recent snowfall overlies a melt-freeze crust in many areas. My best guess is that stubborn wind slabs exist in high north-facing terrain while warm temperatures and solar radiation may have created moist surfaces everywhere else. If there is a good overnight freeze these surfaces will form a hard crust. The deep facet/crust persistent weakness buried at the beginning of February (now down up to 80-100+ cm) should stay on your radar, especially on all alpine slopes during sunny periods. Any activity at this interface would be large and destructive. Also, give large sagging cornices a wide berth when traveling on or below corniced ridges.

Problems

Wind Slabs

Fresh wind slabs could form in exposed lee terrain at higher elevations over the next couple days. Triggering is more likely on steep unsupported slopes near ridge crests.

Avoid freshly wind loaded features.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Large cornices loom above many alpine slopes and will become weak with daytime warming. Give cornices a wide berth while traveling on or below ridges.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Deep Persistent Slabs

The potential for deep persistent slabs will increase when the sun is shining, temperatures are warm or when rain falls. Minimize exposure to big alpine slopes when things are warming up.

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

Expected Size

3 - 6

Valid until: Apr 25th, 2014 2:00PM