Archived

Avalanche Forecast

Jan 21st, 2013–Jan 22nd, 2013

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

Be increasingly cautious with daytime heating on solar aspects.

Weather Forecast

High pressure ridge bringing mild temperatures and mostly clear skies with a strong temperature inversion today. This ridge is expected to last until Tuesday evening.

Snowpack Summary

Upper 25cm is settled snow, with variable wind affect above tree line. The mid pack is well settled. A profile in the Hermit area, 2270m, SE aspect, 28deg, showed a 187cm snowpack with moderate to hard test results, resistant planar down 18, 24 and 48cm. The January 4th surface layer was down 48cm and the November 6 crust was down 140cm.

Avalanche Summary

3 natural loose size 2.0 avalanches from solar radiation east of Rogers Pass summit1 natural slab size 1.5, suspect on Jan 4th layer in Hermit area.

Confidence

on Monday

Avalanche Problems

Loose Dry

Mild alpine temperatures and clear skies will increase the hazard on sun affected slopes. Be mindful of overhead hazards like cornices that may fail with heat and rocky outcroppings where loose avalanches originate.

Pay attention to overhead hazards like cornices.

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

Elevations: Alpine.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Wind Slabs

South winds from earlier in the week had affected much of the tree line and alpine. Wind slabs may still react to skier triggering and may be weakened with warming temperatures.

Caution in lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2

Persistent Slabs

A persistent layer down ~40cm remains a concern. It has been most reactive on steep, solar aspects and produced several skier triggered avalanches last week. Human triggering is still possible.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3