Archived

Avalanche Forecast

Nov 26th, 2016–Nov 27th, 2016

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

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

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

Regions: South Columbia.

New snow has increased avalanche danger in the South Columbia mountains. Make conservative terrain choices until conditions improve.

Confidence

Moderate -

Weather Forecast

Moderate to strong southerly winds will continue on Saturday evening before easing overnight. Sunday will see continued light snowfall and light winds shifting from southwesterly to westerly. Temperatures will begin to cool on Sunday and into early next week. No snow is expected for Monday and Tuesday as cloud cover decreases and winds shift to the northwest.

Avalanche Summary

Although stormy weather allowed only limited observations, skier triggered size 1 and natural size 2+ avalanches were reported in Rogers Pass on Saturday. Explosives control in the Revelstoke area on Friday also yielded numerous size 2 results with slab thickness reaching up to 80cm in depth. Storm slab avalanche activity is expected to continue with ongoing wind redistribution.

Snowpack Summary

Up to 25 cm of new snow fell on Saturday under moderate to strong southerly winds. This new snow now covers the already touchy wind slabs that existed in exposed areas at treeline and above. Several interface layers exist within the snow above the November 13 crust, most notably a sun/temperature crust which formed on steep solar aspects on November 22. The November 13 crust now lies up to a metre below the surface. Below this crust the mid and lower snowpack are well consolidated, with moist snow present at treeline and below.

Avalanche Problems

Storm Slabs

A heavy snowfall on Saturday has increased the size and likelihood of triggering storm slab avalanches, especially in exposed lee terrain. This increased load has the potential to trigger deeper instabilities.

Use caution in lee areas in the alpine and treeline. Storm snow is forming touchy slabs.Use ridges or ribs to avoid pockets of wind loaded snow.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 2 - 3