Avalanche Forecast

Issued: Apr 27th, 2015 4:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wet Slabs, Loose Wet and Cornices.

ian jackson, Parks Canada

Banff Yoho Kootenay.

Tuesday afternoon looks warm with a weak freeze in the AM. If you are going out, start really early and be back before noon when the temperatures are forecasted to be at their peak!

Summary

Weather Forecast

Warm temperatures and clear skies on Tuesday with freezing levels rising to 3000m by 11 am. Tuesday night, a cold front will pass through with 5-10 mm of precipitation (some rain at lower elevations) and winds switching to the west. Wed and Thursday look to be partly cloudy with minimal precipitation and freezing levels dropping to 1500- 2000m.

Snowpack Summary

Recent strong winds have blown dry snow on N aspects into hard windslabs in exposed terrain. Cool temps have kept sheltered high elevation N aspects dry; however warm temps over the next few days will change that. Crusts on all other aspects. The basal facets remain dormant though a large cornice load or intense heat may change this.

Avalanche Summary

A few solar triggered slides off of steep solar aspects today. No other avalanches seen or reported.

Confidence

Problems

Wet Slabs

Warm temperatures will likely awaken deeper layers and trigger some large avalanches on Tuesday afternoon.

Travel early before the heat of the day, and avoid big slopes in the afternoon.Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Loose Wet

We will start to see in increase in solar triggered avalanche activity on Tuesday as the temperatures rise during the day.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. Travel early before the heat of the day, and avoid big slopes in the afternoon.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

We expect multiple cornice failures on Tuesday with the warming temperatures. Each cornice that falls will have a higher chance of triggering the basal weaknesses as the temperatures rise.

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

Likely

Expected Size

2 - 3

Valid until: Apr 28th, 2015 4:00PM