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

Avalanche Forecast

Dec 19th, 2018–Dec 20th, 2018
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
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
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Avalanche danger will be increasing over the next 48hrs with the incoming storm, warm temp's, and strong winds. Conservative route selection is critical right now. Weak layers in the upper snowpack will be tested by the next storm!

Weather Forecast

A trace of snow today with moderate SW winds and a freezing level around 1200m. Thursday brings 25-30cm, strong SW winds, and freezing levels rising to 1500m. Friday will bring in calmer weather, with freezing levels dropping to valley bottom and isolated flurries.

Snowpack Summary

25cm in past 36hrs, warm temp's, and moderate winds are building reactive storm slabs. The Dec 9 surface hoar/facet/crust persistent weak layer is buried 80cm+ and is producing large whumphs and sudden planar results. The Nov 21 surface hoar/facet persistent weak layer is down ~120cm.

Avalanche Summary

10 avalanches to sz 3 were observed in the highway corridor east of Rogers Pass yesterday. Ski tourers at McGill shoulder were able to ski cut surface slabs to sz 1, 15-25cm deep, 10-15m wide along the ridge crest. These slabs were in wind-effected terrain and stopped moving once the slope angle mellowed to <25*.

Confidence

Avalanche Problems

Storm Slabs

25cm in the past 36hrs, accompanied by moderate winds and warm temp's, is forming into a cohesive surface storm slab. These will be found in immediate lee features below ridge crests and on cross-loaded slopes.
If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Avoid convexities and unsupported features.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

The Dec 9 weak layer is down 70-100cm and consists of surface hoar, facets, and sun crust, depending on the aspect. Sudden planar results are being seen on this layer. 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