Avalanche Forecast

Issued: Mar 16th, 2015 11:26AM

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

jlammers, Avalanche Canada

South Rockies.

If solar radiation is strong on Tuesday, the Avalanche Danger may rise to High. Be conservative in your terrain selection as the snowpack adjusts to the shock of recent heavy rain, snow, and now sun.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

Mostly clear skies are forecast for Tuesday as a ridge of high pressure strengthens. On Tuesday night and Wednesday, expect light snowfall (up to 10cm) as a weak front spreads moisture to the region. On Thursday, the region should see a mix of sun and cloud with possibility of snowfall towards the end of the day. Winds should remain generally light, ramping up to moderate from the southwest as Thursday's system rolls in. Freezing levels should hover around 1800m on Tuesday, 1900m on Wednesday and 2000m on Thursday.

Avalanche Summary

At the time of publishing this bulletin no new avalanche activity had been reported. My best guess is that there was a healthy round of storm slab activity in response to all the new snow and wind on Sunday. Looking forward, I`m sure the new storm slab will remain sensitive to human triggering in high elevation, wind-exposed terrain. Also, sun on Tuesday will likely spark a round of loose wet/ wet slab avalanche activity on steeper, sun-exposed slopes.

Snowpack Summary

Heavy rain (up to 60 mm) on Saturday soaked the snowpack. On Sunday the rain changed to snow as the freezing levels slowly dropped. Heavy snowfall (up to 50cm) combined with strong southwest winds developed new storm slabs on all aspects in the alpine and at treeline. The most prominent snowpack feature is a thick crust 10-30cm below the recent storm snow extending up to around 2200m elevation. Below this elevation the crust is effectively capping the snowpack, preventing riders from stressing deeper persistent weak layers. In high alpine areas where the crust is not present or is less thick, dormant persistent weak layers may still be lingering and could wake-up with recent heavy loading or strong warming.

Problems

Loose Wet

The new snow may fail as a pushy loose wet avalanche when it sees direct sunlight for the first time. Keep your eye on the thermometer and watch your overhead hazard as these avalanches may travel long distances and entrain mass quickly.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be alert to conditions that change with aspect, elevation and time of day.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Storm Slabs

Heavy snowfall on Sunday has created deep new storm slabs which will likely remain sensitive to human triggering, especially in higher elevation lee terrain. Recent snow and wind has also created weak and fragile cornices.

The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Mar 17th, 2015 2:00PM