Avalanche Forecast

Issued: Apr 3rd, 2015 8:00AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Storm Slabs and Persistent Slabs.

andrew jones, Parks Canada

Glacier.

Several instabilities still exist in the upper snowpack above treeline. Hazard will rise if forecasted clouds give way to the strong April sun.

Summary

Weather Forecast

Sunny skies cloud over by mid-morning with isolated flurries and trace accumulation throughout the day. Freezing levels will rise rapidly and hover around 1700m this afternoon. Ridge winds remain moderate from the SW. Daytime warming and overnight freezing will be the norm for the next several days. A front will bring 10cm snow on Saturday.

Snowpack Summary

Daytime warming and overnight freezes are influencing the snowpack. A10cm surface crust at 1300m this morning will likely brake down by mid-afternoon. Above treeline, 35cm of dry snow overlies 50cm of moist snow. A 6cm wet snow layer down 50cm and several crusts down 40 to 100cm may be triggerable by light loads. Suspect wind slabs near ridges.

Avalanche Summary

No new natural avalanches were observed in Glacier National Park yesterday.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Wind Slabs

Moderate winds have been shifting from the SW to the NW forming pockets of wind slab on lee alpine features. Due to the variable wind direction they may exist in unusual places.

Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.Stay well to the windward side of corniced ridges.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Storm Slabs

Up to 60cm of new snow exists at higher elevations. Tests show poorly bonded storm snow where buried crusts are present. Hazard will increase when the new storm snow gets a rapid warm up this morning, especially if forecasted clouds don't arrive.

The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A series of weak layers in the top 1.5m of the snowpack are more easily triggered due to the load added by the new snow and rain over the past week. They may be triggered by the added load of a person, another avalanche or a cornice falling.

Pay attention to overhead hazards like cornices.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 4th, 2015 8:00AM