Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Overall, the avalanche hazard will be lower over the next few days as we enter a cooler period following a warm spell, but sunny periods midday Monday will increase the potential for the new snow to fail on recent crusts.
Start early. Finish early.
Click the link for more info on spring conditions.
Confidence
High
Avalanche Summary
Pretty quiet Sunday with mainly cloudy skies and cooler temperatures.
Solar heating Friday and Saturday led to the peak heating event so far this season with widespread loose wet avalanche activity on steep solar slopes. As upper snowpack crusts broke down, small alpine point releases gained mass at lower elevations reaching up to sz 2.
The heating also led to cornice releases and a few significant persistent slabs failing in the alpine in surrounding areas as well
Snowpack Summary
A few cm of new snow sits on surface crusts that exist to ridgetops on solar aspects, and on all aspects to around 2600m.
North alpine slopes hold 5-15 cm of dry snow over firmer surfaces. The March 27 crust is 30-70 cm deep and extends to about 2500 m on North slopes, reaching the ridgetop on solar aspects.
Below the settled mid-pack, weak facets and depth hoar remain.
Weather Summary
Freezing levels peaked around 2200m Sunday with periods of snowfall / rain.
Overnight freezing levels will drop to 1500m before climbing as high as 2500m Monday with some potential for sunny periods midday.
West winds will increase through Monday reaching strong values in the alpine and will bring some precip overnight into Tuesday.
Terrain and Travel Advice
- A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.
- Start your day early and be out of avalanche terrain during the heat of the day.
Avalanche Problems
Loose Wet
Monitor the overnight crust recovery, daytime temperatures, and solar inputs.
The likelihood of loose wet avalanches will increase as temperatures rise and with even short periods of solar inputs as the day progresses.
Pick a good freeze. Start and finish your day early.
Aspects: East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5
Persistent Slabs
An 80 cm thick midpack slab sits over a weak, facetted base. On most slopes, sun crusts and a buried March 27 rain crust cap this slab, adding strength as long as they remain frozen.
The heating event made this problem easier to trigger this weekend and this is likely to happen again at the end of the week.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely
Expected Size: 2 - 3