Avalanche Forecast
Issued: Apr 23rd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
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Avalanche Canada
Expect continued snow up high, rain down low, and a sloppy mix in the middle. Warm temperatures, rain, and the lack of overnight freeze zaps the strength out of the snow.
Summary
Confidence
Low
Avalanche Summary
No new reports of avalanches on Friday or Saturday. Please remember there are few eyes out in the mountains still submitting regular reports.
Expect Storm Slab or Wind Slab avalanches on Monday where more than 20 cm of new snow accumulates. At low elevations avalanche activity is likely to increase as low elevation snow becomes saturated by rain.
Snowpack Summary
Snow continues to accumulate at high elevations on northerly aspects. Generally this recent snow is settling and bonding about as fast as more arrives. Storm slabs may develop in with forecast snow. Windslabs are possible in immediate lee features.
On solar aspects at all elevations, and north aspects at treeline and low elevations, there are many crusts in the upper snowpack. Watch for this snow sitting on a slippery crust. Watch for the snow quickly loosing strength and loose wet avalanches when the sun pokes out.
A layer of surface hoar from March 31 persists down roughly 50 to 100 cm appears to be variable in its distribution. The surface hoar may be sitting above a crust on all but true north-facing slopes. Additional crusts dating from April 7 and April 16 are higher up in the snowpack with similar characteristics and concerns.
The mid-snowpack is strong. However, the November depth hoar remains at the base of the snowpack and remains a concern in rocky, shallow, variable depth snowpack areas at treeline and above.
Weather Summary
Sunday Overnight
Cloudy. Precipitation 5 to 10 mm falling as snow in the alpine, rain down low, and sloppy snow in between . Light southwest winds. Treeline temperatures around zero and freezing level around 2000 m.
Monday
Mostly cloudy. Trace to 5 mm water equivalent of precipitation (rain low, sloppy snow around treeline, snow alpine). Freezing level remaining between 1500 to 2000m. Treeline temperature around zero. Light westerly wind.
Tuesday
Generally clearing up and drying out kind of day. Trace of precipitation. Ridgetop wind light but gusting moderate from the west. Temperatures near zero at treeline with freezing level around 2000 m.
Wednesday
Mix of sunshine with cloud arriving late in the day and precipitation starting up. A trace of preciptiation. Moderate southwest wind, freezing level around 2000 m, treeline temperature around zero.
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.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Storm Slabs
Storm slabs are possible at high elevations where dry snow exists. Watch for wind slabs on lee features. Dial back your terrain choices if you encounter more than 20 cm of new snow. Watch for this snow sitting on a slippery crust on solar aspects. Expect conditions to change as you gain elevation or switch aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Warm temperatures and new snow may increase the sensitivity of this lingering problem. Multiple crusts in to top 80 cm appear to be most reactive on solar tilted slopes where surface hoar may sit on a hard melt-freeze crust. Loose wet avalanches from above could step down to these layers.
Aspects: East, South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.
Suspect terrain includes steep, shallow, and rocky terrain where the snowpack varies between thin and thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 24th, 2023 4:00PM
