Archived

Avalanche Forecast

Mar 23rd, 2015–Mar 24th, 2015

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

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

Regions: Glacier.

Many reports of skier triggered avalanches from neighboring areas over the last two days failing in the top 60cm. The snowpack in Glacier Park is very similar to these places so using conservative terrain is highly recommended.

Weather Forecast

Unstable weather pattern over the Interior will keep the skies mainly cloudy today. Lingering flurries are expected with freezing levels to remain below 1500m. Larger diurnal temperature swings are expected for Tuesday and Wednesday before a high pressure ridge sets in and delivers steady warm air into the weekend.

Snowpack Summary

45-50cm of recent storm snow above 1800m, much of that fell as rain below that elevation. The upper 50cm of the snowpack is moist at 1900m with a complex mix of crusts, facetted snow and spotty surface hoar which have been reactive to skier triggering as slab and loose avalanches. The mid Feb surface hoar layer is down ~75cm.

Avalanche Summary

Yesterday, neighboring backcountry users reported touchy conditions outside the Park releasing avalanches and remotely triggering them 30-60cm deep. Numerous loose avalanches from solar radiation on south aspects in the highway corridor. From two days ago a there was a natural avalanche cycle with numerous slab and loose avalanches to size 3.

Confidence

Avalanche Problems

Storm Slabs

40-55cm of heavy storm snow over three days will need some time to settle out and to bond to the crusts over which it lies. The associated winds with the storm were steady creating soft slabs in exposed areas.

Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

The upper snowpack is complex with a multitude of crusts, weak facetted layers, and surface hoar. There have been reports of skier triggered slab avalanches failing down 30-60cm on these crusts from neighboring areas.

Be aware of the potential for large, deep avalanches.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 3