Archived

Avalanche Forecast

Mar 5th, 2017–Mar 6th, 2017

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

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.

We're entering a period of uncertainty as storm slabs gradually settle and bond to the surface. Avoid pushing into aggressive terrain. Avalanche problems exist at all elevations.

Confidence

Moderate -

Weather Forecast

Monday: Cloudy with scattered flurries bringing around 5 cm of new snow. Light to moderate southwest winds. Alpine temperatures of -10.Tuesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light to moderate south winds. Alpine temperatures of -11.Wednesday: A mix of sun and cloud with isolated flurries and up to 5 cm of new snow. Moderate southwest winds. Alpine temperatures of -10.

Avalanche Summary

Saturday's reports show a continuation and increase from Friday's activity. with numerous storm and wind slab releases generally from Size 1.5-2.5, with a few larger and smaller examples. Natural triggers figured prominently in the reports, but ski cutting and explosives were also employed to mitigate avalanche hazards. All aspects shared fairly equal representation. Our mid-February interface was again noted as a failure plane in several occurrences, yielding both natural and skier triggered releases to Size 2.5. Crown fractures averaged about 30-70 cm, but several were noted at 80-100 cm.Looking forward, expect a decline in natural avalanche activity while the potential for human triggering to the full depth of our new snow lingers for a few more days.

Snowpack Summary

Just under a week of stormy weather has delivered a wide-ranging 65-120 cm of new snow to the region. Moderate to strong southerly winds accompanied the new snow, promoting touchy storm slab formation at all elevations. The new snow has buried widespread faceted surface snow, thin sun crust on steep solar aspects, as well as more isolated surface hoar to 4mm. About 90-135cm below the surface you'll find the mid-February interface which is composed of a thick rain crust up to about 1800 m, sun crusts on steep solar aspects, and spotty surface hoar on shaded aspects. This layer has seen a recent increase in more sudden snowpack test results and has been identified as a failure plane in a number of recent avalanches. Its reactivity has been especially prominent over the crust at lower elevations. Any continuing activity at this interface will likely see it emerge as a persistent weak layer. Below it, the mid and lower snowpack are generally well settled and stable.

Avalanche Problems

Storm Slabs

As natural avalanche activity subsides, potential for human triggering storm slabs will persist. The touchiest conditions have been reported in wind affected areas and where the new snow overlies crust. (Steep south-facing slopes and below treeline)

The new snow will require several days to settle and stabilize.Be alert to conditions that change with elevation.Be increasingly cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 3