Avalanche Forecast

Issued: Mar 28th, 2016 9:17AM

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

jlammers, Avalanche Canada

South Rockies.

The Avalanche Danger will be higher in areas east of the divide where heavy snowfall was noted on Monday. Forecast solar radiation will add to the reactivity of the new snow making large avalanches more likely.

Summary

Confidence

Moderate - Due to the number of field observations on Monday

Weather Forecast

A ridge of high pressure will dominate the province bringing a mix of sun and cloud for the forecast period. Ridgetop winds will be strong from the northeast on Tuesday, and then become light for Wednesday and Thursday. The freezing level will rising gradually from about 2000m on Tuesday to about 2600m by Thursday.

Avalanche Summary

No new avalanches were reported on Saturday. I expect a new round of storm slab activity in response to new snow and wind on Sunday night and Monday. Solar warming will become the driver for natural avalanche activity throughout the forecast period. With that, I'd add loose wet avalanches and cornice falls to the mix.

Snowpack Summary

Moderate to heavy snowfall and wind on Monday are expected to form potent new storm slabs. A moderate westerly flow will taper-off, and extreme northeasterly winds are expected at the tail end of the system. With that, I'm sure the wind-effect will be variable and new wind slabs will be found in unsuspecting locations. The new snow will overlie stubborn wind slabs in shaded high elevation terrain and a hard crust in most other places. Deeply buried weak layers near the ground are becoming hard to find, but may remain sensitive to triggering from significant warming or with large loads such as cornice fall. Large cornices overhang alpine slopes and will become increasingly weak with forecast solar radiation.

Problems

Storm Slabs

On Monday heavy snowfall was noted in areas east of the divide. Potentially extreme northeast winds will have redistributed the new snow creating hard slabs on solar aspects. Solar radiation may add to the reactivity of the new snow.

Choose conservative lines and watch for clues of instability.>Be cautious as you transition into wind affected terrain.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 4

Cornices

Large fragile cornices threaten many slopes and will become increasingly touchy with solar radiation. A cornice fall could be the large trigger required to awaken destructive buried weak layers.

Do not travel on slopes that are exposed to cornices overhead.>Stay well to the windward side of corniced ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Loose Wet

Watch for pushy loose wet avalanches at all elevations throughout the forecast period. The combination of new snow, buried crusts and solar radiation will make conditions extra touchy on sun-exposed slopes.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Mar 29th, 2016 2:00PM