Avalanche Forecast

Issued: Apr 6th, 2016 8:46AM

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

jsmith, Avalanche Canada

Kootenay Boundary.

Freezing levels skyrocket to the moon on Thursday. Watch out for failing cornices and expect a widespread loose wet avalanche cycle on solar aspects in the alpine.

Summary

Confidence

High

Weather Forecast

THURSDAY: Freezing levels skyrocket to 3500m, sunny, light southwest ridgetop winds. FRIDAY: Freezing level 3500m, sunny, light southwest ridgetop winds. SATURDAY:Â Freezing level 3000m, sunny, light southwest ridgetop winds.

Avalanche Summary

No new avalanches were reported in this region on Tuesday. However, I expect to see widespread natural avalanche activity on Thursday when the recent storm snow is heated by solar radiation and soaring freezing levels.

Snowpack Summary

Large cornices overhang alpine slopes and may trigger large, destructive avalanches running to valley bottoms. Up to 20cm of recent storm snow with moderate northwesterly winds will have created wind slabs on lee aspects in the alpine and open treeline. These wind slabs will increase in sensitivity when they are warmed up for the first time by solar radiation and rising freezing levels. The late February surface hoar/ crust interface down 80 to 130 cm. is currently dormant, however, a rapid warm up could awaken this sleeping dragon. At low elevations, the snowpack is isothermal.

Problems

Wind Slabs

Wind slabs become more reactive when heated by the sun for the first time.

Travel on ridgetops to avoid wind slabs on slopes below.>Be cautious as you transition into wind affected terrain.> Be alert to conditions that change with aspect, elevation and time of day.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

This time of year the strength of cornices deteriorates rapidly with solar radiation.

Pay attention to overhead hazards like cornices.>Cornices become weak with daytime heating, so travel early on exposed slopes.>Give cornices a wide berth when traveling on ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

3 - 6

Loose Wet

Changes can be rapid, sometimes significant change is possible in a matter of minutes, certainly within an hour or two.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Valid until: Apr 7th, 2016 2:00PM