Archived

Avalanche Forecast

Apr 11th, 2023–Apr 12th, 2023

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

Alpine

1: Low

The avalanche danger rating in the alpine will be low

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: East Island, North Island, South Island, Vancouver Island, West Island.

Lingering wind slabs may remain reactive to human triggers on lee aspects at treeline and above.

Watch for recently formed and reactive wind slabs as you transition into wind affected terrain.

Confidence

Moderate

Avalanche Summary

Several skier triggered small (size 1) 20 cm deep wind slabs were reported on northerly aspects at treeline near Mt. Washington on Monday.

Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.

Snowpack Summary

Around 25-50 cm of heavy, wet new snow exists between 1000-1400 m. Above 1400 m, dry snow has likely been redistributed into deeper deposits on north-facing terrain features by strong southerly winds. Below 1000 m, rain has saturated the snowpack.

The storm snow sits over a melt-freeze crust at mid-elevations, and over settling dry snow at high elevations on shaded slopes. The middle and lower snowpack is strong and well-bonded.

Weather Summary

Tuesday night

Partly cloudy with flurries; 5-10 cm / 20 km/h south ridgetop wind / Temperature at treeline around -3 C / Freezing level 600 m

Wednesday

Sunny / 10 km/h northwest ridgetop wind / Temperature at treeline around 3 C / Freezing level rising to 1400 m

Thursday

Cloudy / 10 km/h southwest ridgetop wind / Temperature at treeline around 0 C / Freezing level 1000 m

Friday

Mostly cloudy with isolated flurries; 3-10 cm / 30 km/h south ridgetop wind / Temperature at treeline around 1 C / Freezing level 1100 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Back off slopes as the surface becomes moist or wet with rising temperatures.
A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.

Avalanche Problems

Wind Slabs

Lingering wind slabs may remain reactive to human triggers on lee aspects at treeline and above.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2.5

Loose Wet

Expect the sunshine to trigger small wet loose avalanches on slopes that are still holding dry snow at upper elevations.

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

Elevations: Alpine.

Likelihood: Very Likely

Expected Size: 1 - 1.5