Archived

Avalanche Forecast

Mar 29th, 2017–Mar 30th, 2017

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

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.

Substantial precipitation in March combined with mild temperatures has meant a lengthy time period of increased avalanche hazard. Don't let your guard down yet, cooling temperatures is needed before stability can improve.

Weather Forecast

A low pressure system is forecast to move across Rogers Pass today, shedding 10-15cm of precipitation (snow or rain depending on elevation), FL rising to 1800m and blustery wind from the south. Flurries/showers tonight into early tomorrow than the start of a high pressure pushes through for Friday.

Snowpack Summary

Spring crusts are stacking up: March 27 CR is down 15cm, March 19 CR is down 35cm, March 16 CR is down 60cm and the Feb 19 CR is down 150cm @ TL. These layers are potential sliding surfaces as loose wet or moist slab avalanches. Storm slabs in the alpine will be a major concern today especially this afternoon.

Avalanche Summary

Yesterday we observed one size 2 avalanche in the highway corridor on steep, unsupported Nth facing terrain in the alpine and one glide avalanche size 2 below tree line on a south aspect. On Monday when the sun came out in the afternoon a small loose wet cycle started to size 2 on steep, solar asp.

Confidence

Intensity of incoming weather systems is uncertain on Wednesday

Avalanche Problems

Storm Slabs

Lots of uncertainty in the alpine currently with limited field observations. We should apply a significant margin of safety when assessing terrain, giving convexities and tension areas of the snow pack a wide berth.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Loose Wet

Warming temperatures can cause new snow over crusts to quickly become touchy and slide easily as loose wet or moist slab avalanches.

If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3

Cornices

Cornices are very large right now and can fail unpredictably - if this happens persistent weak layers deep in the snowpack can be triggered, resulting in very large avalanches.

Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 2 - 3