Avalanche Forecast

Issued: Mar 3rd, 2019 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Dry and Wind Slabs.

william lawson, Parks Canada

Banff Yoho Kootenay.

Clear sky's and warming temperatures this week will likely effect the upper snowpack. Watch for an increase in loose dry avalanche activity on solar aspects with daytime warming.

Summary

Weather Forecast

Hope on the horizon with warming temperatures approaching for the week. Evening temps for the start of the week will continue to be frigid with lows dipping in the mid -20's, but clear sky's and daytime highs around -5 will be a welcome change. With warming temps we can expect solar triggering to become more of a concern southerly aspects.

Snowpack Summary

Prolonged cold temperatures have weakened the upper snowpack. Wind effect is common in the alpine and several recent crusts can be found on steep solar slopes. Despite the weakening slab above it, Jan 17 surface hoar lingers down 40-60 cm in isolated locations and produces hard, resistent shears. A weak basal snowpack exists in thin snowpack areas.

Avalanche Summary

On a flight over the forecast region today we observed a few large triggers (cornice and seracs) impacting slopes below, causing only small avalanches given the size of trigger. The loose dry problem remains the main concern. We continue to see natural and human triggered avalanches out of most steep terrain.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Loose Dry

Cold weather has created weak, faceted surface snow. In steep terrain, these facets are easily triggered and can gain enough mass to affect skiers and climbers. Solar triggering of this problem will be come more of a concern over the next few days.

Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

A mix of fresh and old wind slabs have been stubborn but active, and are likely only to be found in very steep or extreme terrain near wind exposed ridge crests. Pay close attention to the feeling of the surface snow under your feet.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Mar 4th, 2019 4:00PM