Archived

Avalanche Forecast

Feb 24th, 2015–Feb 25th, 2015

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

1: Low

The avalanche danger rating in the alpine will be low

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

1: Low

The avalanche danger rating in the alpine will be low

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

Over the next few days cooling temps will lower avalanche danger. We are in a low probability, high consequence period. Large but difficult to predict avalanches continue to occur sporadically. Watch for solar warming and avoid cornices.

Weather Forecast

The ridge of high pressure will weaken briefly. There will be increasing cloud today, with isolated flurries. Temps should be slightly cooler, with a high of -4, and moderate but gusty westerly winds. Wed and Thursday will be similar. A mix of sun and cloud, light to moderate winds, with alpine high's of -5'C.

Snowpack Summary

Below 1900m a few cm's of snow sits on a hard crust. 15-20cm of snow sit on the Feb 18 surface hoar layer, which exists up to 2200m. The Feb 14 crust is down 20-25 and is up to 10cm thick. Variable wind effect, with pockets of thin hard slab, exists in exposed areas at treeline and above. Persistent weak layers down 1-1.5m are stubborn to trigger.

Avalanche Summary

Yesterday solar with an alpine inversion triggered numerous loose, solar triggered avalanches to size 2. Just outside the park boundary a solar triggered avalanche on a S aspect stepped down to deep persistent layers, propagating 400m wide and was a size 3.5. On solar aspects, small loose avalanches were triggered by riders, running on the crust.

Confidence

Avalanche Problems

Wind Slabs

Variable winds have resulted in wind slabs on exposed slopes. Wind slabs up to 50cm thick could propagate on a buried crust or surface hoar. Cornices are becoming more touchy and have triggered deep slabs recently.

Be cautious as you transition into wind affected terrain.Watch for areas of hard wind slab in steep alpine features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

Deep persistent weak layers will need a large load such as a cornice fall or another avalanche to be triggered. A light load may be able to trigger them from shallow areas. Heads up when traveling on slopes threatened by cornices above.

Extra caution needed around cornices with current conditions.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 3 - 4