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Archived

Avalanche Forecast

Apr 9th, 2023–Apr 10th, 2023
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
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
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

Prepare for a wet and stormy day. Avoid avalanche terrain during periods of heavy loading from rain, snow or wind.

Observe your local conditions, and let that guide your terrain choice. Forecasted snow and rainfall amounts are uncertain.

Confidence

Low

Avalanche Summary

No recent avalanches have been reported. Expect avalanche activity to increase on Monday with the arrival of a wet storm.

If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.

Snowpack Summary

10-15 cm of recent snow in the alpine covers settling, dry snow on shaded (northerly) aspects, and a frozen crust on solar aspects. At treeline, this new snow is likely to be denser, shallower, and moist.

Below treeline, 10-15 mm of rain starts to soak frozen crusts or already wet surfaces, and will be eating away at the snowpack at low elevations.

The mid snowpack is generally settled and strong, except in areas with snow depths less than 150 cm. In these lower snow areas, the mid-pack is likely weaker and more faceted.

The lower snowpack includes a layer of large, weak facets and/or depth hoar crystals.

Weather Summary

Snow/Rain amounts for the incoming storm are uncertain. Weather models are not agreeing on how widespread or intense the precipitation will be. Prepare to continually evaluate the conditions, and change plans as necessary.

Sunday Night

Cloudy. 5-10 cm of snow expected in the alpine, rain below 2000 m. Treeline temperature around 0 °C. Light to moderate southwest ridgetop wind, trending to strong at higher elevations.

Monday

Cloudy. 15-20 cm of snow expected in the alpine, rain below 2000 m. Possible isolated areas of 30mm or more. Treeline temperature around 0°C. Light to moderate southwest ridgetop wind, trending to strong at higher elevations.

Tuesday

Mostly Cloudy. Moderate to heavy rain overnight turning to snow as the snow/rain line drops to 1000 m. 5-10mm, possible isolated areas of 40 mm or more. Light southwest ridgetop wind trending to strong at higher elevations.

Wednesday

Mostly cloudy. 5-10 cm of snow expected. Treeline temperature around -5°C. Light variable ridgetop wind.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Be careful to keep storm day fever from luring you out into bigger terrain features.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Avalanche Problems

Storm Slabs

Storm slabs will be building through the day on Monday.

Strong southwest winds at high elevations could be building deeper, more reactive pockets of slab in leeward terrain.

Storm slabs in motion may step-down to deeper layers in the snowpack that may have been weakened by rising temperatures and/or rain.

Use extra caution around ridgecrests, rolls, and on convex slopes. Retreat to mellower terrain if you find signs of instability like shooting cracks, whumpfs, or recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Loose Wet

At treeline and below, the precipitation will fall as rain, and through the day, the upper snowpack is likely to become wet and unstable.

If you see signs of a rapidly warming snowpack, like snow that feels like a slurpy, or clumps up and pinwheels down a slope, retreat to mellower terrain.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Deep Persistent Slabs

The base of the snowpack remains weak. Avoid thin, rocky start zones and shallow areas with variable snowpack depths.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 4