Archived

Avalanche Forecast

Mar 11th, 2016–Mar 12th, 2016

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

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

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

The sun is triggering both recent windslabs, and cornices today, both are touchy, use caution today.

Weather Forecast

Sunny with cloudy periods, and flurries possible. Light winds from the SE with gusts to 40kph. Freezing line rising to 1900m today. Tonight flurries with 6cm and light S winds gusting to 45kph. Saturday and Sunday bring more snowfall, and gusty winds, with the freeze line rising to 1800m on Saturday.

Snowpack Summary

Windslabs in the Alpine and Treeline are touchy, with surface hoar sitting on thick sun crust. Snowpack test results at Mt Fidelity showed these slabs were ripe to trigger and propagate on a S aspect. Ridge top cornices are weak right now and can trigger deeper layers in the snowpack causing larger avalanches. Sun today will increase hazard levels.

Avalanche Summary

A natural avalanche cycle is currently underway, with numerous sz 2-3's from recent snowfall and strong to extreme winds. A large sz 3.5 from a NE aspect on Parson's Peak in the Bonney drainage was triggered by a cornice fall early this morning and dug down through the entire winters snowpack and in places to glacier ice.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Avalanche Problems

Persistent Slabs

The Feb 27th interface is now down 60cm & is producing sudden planar results on a crust on S though W aspects. Test results on NE aspects showed stubborn results. Wind-loading and solar input will increase it's sensitivity.

Be aware of the potential for wide propagations.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Wind Slabs

Previous southerly winds created windslab on lee slopes and cross-loaded features. While these slabs are gaining strength they still remain a concern for human triggering.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Cornices

The additional storm snow, accompanied by SW winds and mild temp's, has allowed cornices to grow and become fragile. Limit your exposure to these overhanging beasts along the ridge crests. A cornice triggered avalanche on Parsons Peak dug down to ice

Pay attention to overhead hazards like cornices.Give cornices a wide berth when travelling on or below ridges.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4