Archived

Avalanche Forecast

Mar 17th, 2017–Mar 18th, 2017

Alpine

4: High

The avalanche danger rating in the alpine will be high

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 Coast.

Snowfall amounts are uncertain for Friday night. Danger ratings are based on 20-30 cm of new snow, but be prepared to scale back your plans if you see greater accumulations.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY NIGHT: Storm starts with 20-30 cm, strong southwest winds, and freezing level around 1000 m.SATURDAY: Lingering flurries in the morning with freezing level briefly climbing to 1300 m, followed by cooling in the afternoon and moderate west winds. SUNDAY: Clearing skies following the storm as treeline temperatures drop to around -5 C, light winds.MONDAY: Mix of sun and cloud, light winds, treeline temperatures around -3 C.

Avalanche Summary

On Thursday, two large size 2.5-3 avalanches were reported north of Grouse Mountain in a MIN post. (See video here.) The debris was several days old and likely occurred during the heavy rain event earlier this week. Observations throughout the week were limited, but similar natural activity likely occurred throughout the region.On Saturday, expect fresh storm slabs that will be thicker and more reactive at higher elevations and in exposed terrain.

Snowpack Summary

Expect 20-30 cm of new snow by Saturday morning with rising freezing levels creating unstable storm slabs. The recent storm snow sits above a widespread rain crust that will be 30-50 cm deep. Some reports indicate the snow is bonding well to this crust, but that may not be the case everywhere.

Avalanche Problems

Storm Slabs

New snow will form touchy storm slabs on Saturday, especially at higher elevations where winds will form deeper deposits. These slabs may be poorly bonded to the underlying rain crust.

Be alert to conditions that change with elevation.Choose conservative lines and watch for clues of instability.Use caution in lee areas in the alpine and treeline. Storm snow is forming touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 2