Archived

Avalanche Forecast

Feb 5th, 2018–Feb 6th, 2018

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Expect the avalanche hazard to increase on solar aspects with prolonged sun exposure.'The first kiss of the sun' after a storm often triggers a natural avalanche cycle. Human triggering of avalanches remains likely.

Weather Forecast

The first day in awhile that you won't be able to track the hourly snowfall on the brim of your sweet trucker hat. Expect cloud with sunny periods, temps from -4 to -10 and light winds from the west. No forecasted snow today. Another pacific storm is brewing off the coast and will push inland on Tuesday evening into Thursday, 40-50cm expected.

Snowpack Summary

Another 22cm brings the weekly snowfall total to 160cm adding to the already healthy sized storm slab. Previous moderate to strong south winds have created pockets of windslab in the alpine. Over a meter and a half of settling snow sits on the Jan 16th surface hoar, which is the uppermost PWL and is still distinct and easy to pick out on pit walls.

Avalanche Summary

Several natural avalanches reported yesterday from backcountry users up to size 2.5 with crowns up to 1.5m deep. Suspect these deep avalanches failed on the Jan 16th surface hoar layer. Artillery avalanche control on Saturday produced numerous avalanches, size 2.0-3.5, with several avalanches dusting the highway.

Confidence

Timing or intensity of solar radiation is uncertain on Monday

Avalanche Problems

Storm Slabs

Consistent snowfall over the week has created a storm slab. Previous strong South winds have redistributed the new snow into a windslab in the Alpine. If triggered, the slab could step down to deeper persistent weak layers.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

Natural avalanche activity on the persistent weak layers has tapered off recently. The Jan 16th, 4th and Dec 15th surface hoar layers are buried deep, but avalanches in the storm snow can step down and trigger these weak interfaces.

Minimize overhead exposure; avalanches may reach the end of run out zones.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 4