Avalog
Register
Get forecast notifications
Create an account to receive email notifications when forecasts are published.
Register
Login
Archived

Avalanche Forecast

Dec 18th, 2018–Dec 19th, 2018
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
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
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

Regions: Glacier.

Avalanche activity is expected to increase as the storm snow settles into a cohesive slab. Human triggering is likely. Stay in conservative terrain until the storm tappers off in a few days.

Weather Forecast

Another 10-15cm of snow forecasted for the day with an alpine high of -4, winds 30-55kph from the SW and a freezing level rising to 1600m (watch for tree bombs at low elevations). A forecasted 10cm on Wednesday and 30cm on Thursday with moderate - strong winds.

Snowpack Summary

15cm in the past 24hrs accompanied by moderate winds and near zero temps is building a storm slab and buries old wind slab in the Alpine. The Dec 9 surface hoar/facet persistent weak layer is buried 70-100cm and producing large 'whumphs' and sudden planar test results. The November 21st surface hoar/facet persistent weak layer is down 120-160cm.

Avalanche Summary

Several avalanches size 2 to 3 were observed along the highway corridor and several size 1.5 - 2 naturals reported from backcountry users yesterday. Large settlements on the Dec 9 layer are producing 'whumphs' that have traveled for over 100m in open terrain and seem most prevalent at tree line. Limited alpine observations due to poor visibility.

Confidence

Avalanche Problems

Storm Slabs

25cm in the past 36hrs accompanied by moderate winds and near zero temps promoting storm slab formation, particularly on lee and cross loaded features.
If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Avoid convexities and unsupported features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

The December 9 weak layer is down 70-100cm and consists of surface hoar, facets, and sun crust, depending on the aspect and producing sudden planar test results. Natural and human triggered avalanches are still occurring on this layer.
Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 3.5