Avalanche Forecast

Issued: May 1st, 2017 7:53AM

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

Parks Canada chris gooliaff, Parks Canada

The Winter Permit System is finished in Glacier National Park for the winter season and this is the last bulletin. Early starts and finishes are crucial during the warm months of the year, so if you have to get some last turns in, start by headlamp!

Summary

Weather Forecast

With increased daylight hours, there is less time in the night for temp's to drop below freezing. Incoming Spring and Summer storms will likely mean rain to mountain-tops, with the occasional colder storm dropping snow on the highest peaks. 

Snowpack Summary

In May, high elevation N aspects still hold a winter snowpack with surface windslab that may be sensitive to human triggering given the right location. On all other aspects, expect temperature and sun crusts until daytime warming softens the surface. The snowpack is isothermal below these surface crusts at tree-line and below tree-line elevations.

Avalanche Summary

In Spring and early-Summer, avalanche activity can be expected during the heat of the day, during rain events, or at any time if there has not been a good overnight refreeze of the surface crust. 

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs
Dry slab avalanche danger may exist during Spring snow storms in the high alpine.
Use caution above cliffs where small avalanches may have severe consequences.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet
As daily temp's continue to increase with the arrival of summer, the loose wet avalanche problem will move higher into the alpine. Pay attention to the thickness of the surface crust and its strength as the day progresses.
Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Use extra caution on solar slopes or if the snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices
Cornices are huge and hanging over alpine lee slopes in many places. Daytime warming may promote failure of these large triggers. Cornice failure may trigger deep slabs.
Cornices become weak with daytime heating, so travel early on exposed slopes.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: May 2nd, 2017 7:53AM