Archived

Avalanche Forecast

Jan 2nd, 2014–Jan 3rd, 2014

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

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

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.

Increasing avalanche hazard today with the incoming storm. Give overhead avalanche paths a wide berth, especially during periods of heavy snowfall.

Weather Forecast

A winter storm is forecasted to arrive in the area later this morning, bringing anywhere between 10-30cm of snow, with moderate to strong W winds and freezing levels rising to 1400m.

Snowpack Summary

35cm of recent snow is settling. Mid to lower snow pack is rounding out and becoming more settled. The Dec. 8 surface hoar/facet layer, down ~90cm, is mostly unreactive in snowpack tests around Rogers Pass. The Nov. 28 surface hoar layer, down ~125cm, is still well preserved in certain areas and is giving hard sudden planar results.

Avalanche Summary

No new avalanches were observed in the highway corridor yesterday. Ski operations adjacent to Glacier National park observed a few slab avalanches within the storm snow, less than 30cm in thickness. As the new storm system rolls in, expect natural activity to pick up.

Confidence

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

Avalanche Problems

Storm Slabs

Storm slabs will become an issue at the peak of the incoming system. Strong winds and warm temp's accompanying the new snow will develop slabs quickly in exposed lee features at all elevations.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2

Wind Slabs

Wind slabs are still reactive to rider triggering in the upper snowpack. Large planar or unsupported slopes should be treated with respect.

Dig down to find and test weak layers before committing to a line.Avoid freshly wind loaded features.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

A deep persistent weakness lingers, down roughly 120cm. It will take a large trigger to initiate this layer, but if it starts to move, propagation would likely be wide and deep, creating a larger avalanche.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely

Expected Size: 2 - 4