Archived

Avalanche Forecast

Jan 29th, 2013–Jan 30th, 2013

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Cariboos.

If more than 15 cm of snow lies on the ground Wednesday morning, consider danger to be HIGH in the Alpine and at Treeline.

Confidence

Poor - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

Synopsis: Continued northwesterly flow will bring moderate or locally heavy pulses of precipitation to the region interspersed with some dry patches.Tuesday night: 10-15 cm low density new snow.Wednesday: Another 10-15 cm new snow through the day. Treeline temperatures should peak around -4C. Northwesterly winds gusting to 60 km/h.Thursday: Light snowfall, 2-4 cm. Temperatures rising in the afternoon to around -1C at treeline. Moderate northwesterly winds.Friday: Some clear spells and some flurries. Temperatures around -4C at treeline. Moderate northwesterly winds.

Avalanche Summary

No new avalanches reported from this region.

Snowpack Summary

Around 40-50 cm recent new snow has settled into a 20-30 cm soft slab overlying a weak layer comprising of facets at higher elevations, surface hoar on shady slopes, and a sun crust on solar aspects. The recent new snow sitting above this interface has been slowly consolidating from fresh powder into a more cohesive slab. As this process continues, the avalanche character will change from relatively harmless loose sluffs to more dangerous slab avalanches. However, note this upper weak layer has been reported to be patchy and variable in distribution. A mid-pack layer buried in early January surface hoar layer is down 70-90 cm. While this layer is still on the radar of professional observers, with most likely trigger points being on steep rolls below 1600 m, there has only been one small avalanche (size 1 at 1200 m on a north aspect) reported on this layer from the region for approximately 10 days.

Avalanche Problems

Wind Slabs

Forecast new snow and northwest winds will likely set up fresh wind slab on south and east aspects in exposed lee terrain. Old wind slabs exist on north aspects.

Avoid freshly wind loaded features.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

Two surface hoar layers lie buried under the surface, one approximately 40cm down and the other approximately 80cm down. Both are reported to be patchy and variable in distribution. Most likely triggered on steep convex rolls at treeline or below.

Whumpfing is direct evidence of a buried instability.>Avoid steep convex rolls at and below treeline where buried surface hoar may be preserved.>Dig down to find and test weak layers before committing to a line on steep slopes in open glades.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 5