Avalanche Forecast

Issued: Apr 27th, 2014 9:15AM

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.

swerner, Avalanche Canada

South Rockies.

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

Summary

Weather Forecast

Synopsis: A strong upper ridge will build over the region on Monday and dominate through the week. This will bring mostly sunny skies, and moderate SW-W ridgetop winds. Freezing levels will rise to 1800 m on Monday and then climb steadily above 2000 m from Tuesday onward. No significant overnight freeze is expected.

Avalanche Summary

There are no recent reports of avalanche activity from the region. It's likely that any recent activity is a result of daytime warming, solar radiation , and/or periods of rain. We should see a return of warm sunny weather next week. When this happens expect a spike in loose wet activity, cornice releases, and sporadic deep slab avalanches.

Snowpack Summary

This is a broad general summary of conditions in the region based solely on recent weather data and previous snowpack information. It should be supplemented with local observations to help assess avalanche danger. Please refer to this document for additional snow and avalanche information and general travel advice.Over the past week we have seen light precipitation with a snow line somewhere around 1800 m (+/- 200 m). 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.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

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.

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

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Deep Persistent Slabs

This problem remains unlikely but should stay on your radar, especially as we transition into much warmer spring weather later this week.

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 28th, 2014 2:00PM