Archived

Avalanche Forecast

Jan 2nd, 2019–Jan 3rd, 2019

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

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

4: High

The avalanche danger rating below treeline will be high

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

4: High

The avalanche danger rating below treeline will be high

Regions: Glacier.

A significant winter storm is heading our way today and will increase the Avalanche Hazard over the next few days. Expect Artillery Avalanche Control and Highway closures on Thursday.

Weather Forecast

A significant storm system will arrive today and persist until Friday evening with a forecasted snowfall amount of 80cm with moderate to strong winds. Today we will see ~10cm of snow, an alpine high of -7 and 30kph Southerly winds. Snowfall amounts are forecasted to be; 20cm tonight, 30cm tomorrow, 20cm Friday... Wahoo!

Snowpack Summary

40cm of storm snow has been redistributed by moderate southerly winds. The Dec 9 and Nov 21 interfaces are down ~120-160cm and still producing hard/sudden test results, and can be triggered in shallow/rocky areas. The mid to lower snowpack is generally well settled and rounding. Decomposing early seasons crusts are still present at/near the ground.

Avalanche Summary

A skier triggered size 3 avalanche from Bruins Ridge nearly swept 2 skiers over cliffs into 8812 Bowl on Sunday. A field team found the avalanche slid on the Nov 21 sun crust, triggered from a shallow area. The crown ranged from 30-150cm in thickness, 40m wide, and 300m in length. No new avalanches observations or reports yesterday.

Confidence

Avalanche Problems

Storm Slabs

A new storm slab will develop over the day with the incoming storm and bury old wind/storm slab. 40cm of settled storm snow has been redistributed by moderate southerly winds and formed pockets of wind slab at ridge line and cross loaded features.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Assess start zones carefully and use safe travel techniques.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2.5

Persistent Slabs

The Dec 9/Nov 21 persistent weak layers are down ~120cm+ and consist of surface hoar, facets, or a sun crust depending on aspect and elevation. Sunday's Bruins Ridge avalanche was triggered on this layer in a shallow, wind-swept area.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3