Archived

Avalanche Forecast

Dec 2nd, 2020–Dec 3rd, 2020

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

Expect Natural Avalanches this afternoon as temperatures heat up in the alpine!

Weather Forecast

A strong High-Pressure system from the south of the border will produce an inversion with; unseasonably warm temperatures in the Alpine, sunny skies, light wind. Freezing level could reach 3500m today, dropping to HWY elevation overnight. Tomorrow the inversion will hopefully subside a little with the FL only forecast to reach 1800m.

Snowpack Summary

5-10cm of new snow, and moderate wind has hidden a widespread layer of surface hoar size 5-10mm in sheltered areas. Beneath this interface are old wind slabs in the Alpine and exposed areas of treeline. In sheltered areas around TL there is another buried layer of SH dwn 40-60-cm. The Nov 5th Cr is now buried over 1m down

Avalanche Summary

A few loose dry avalanches were obs in the Park yesterday. They occurred on solar aspects, starting from steep unsupported, rocky terrain features. A size 2.5 wind slab, and a cornice fall were also noted, that probably failed Monday evening with the strong winds. Big lines have been ridden recently, with little avalanche activity observed.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Loose Dry

A strong inversion today will provoke a loose dry avalanche cycle @ Rogers Pass, and potentially loose wet avalanches also. These will be most likely on steep S-SW aspects with rocky terrain features, but keep your guard up on other aspects too.

While traveling at lower elevations, pay attention to overhead avalanche paths this afternoon!

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2

Wind Slabs

Previous moderate-strong SW winds formed windslabs in open wind affected areas in the alpine and at treeline. In sheltered areas these wind slabs may overly a few preserved surface hoar layers. One buried ~10cm and the other~30-50cm.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

Today's high temperatures will be a test to see if this dormant layer wakes up? We have not seen much reactivity in the last week on the Nov 5th. Heavy loads like large cornices have failed to step down to this interface recently.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 3