Avalanche Forecast
Issued: Dec 30th, 2020 1:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wet Slabs, Loose Wet and Storm Slabs.
Bill Phipps,
VIAC
Well it was a big day for the mountains on Monday.... Lots of folks out and an active snowpack. The new snow that fell Sunday night into Monday morning was moving on the firm crust below especially in wind loaded pockets. Numerous loose day avalanches were triggered by folks up to size one island wide. Two size one wind/storm slab avalanches were human triggered in the Forbidden plateau zone. One size two was skier triggered in the southern zone (Port Alberni) that took a skier for a ride without injury. All of these were skier triggered and were associated with convex rolls in the terrain. Its all a good reminder that though our island snowpack is know for being stable...... it can be a sleeping giant. Folks need to remember to not be complacent and get lulled by our desire to rip it when things look so nice (a mistake which I am fully guilty of as well).
Huge thanks to all that sent info in over the past couple days. This info (esp avalanche incidences) is super valuable to the safety of all us mountain folks in this community of ours. Cheers to Stephan, Mike, Andrew, Kalen, Markus, Faelan, Gord, Peter and Richard for all their public reports. Also for the continued support of the local companies that send us snowpack data, Jan and crew at Island Alpine Guides, Cliff at Strathcona Mountain Adventures and the Ski Patrol at Mount Washington Alpine Resort. We can't do this without you all...
Summary
Past Weather
Sunday night an average of 10 to 20 cm of nice powder snow fell on a crust island wide with a big 30-40 cm for the southern zone (Port Alberni) and unfortunately very little to none for the northern zone (Mt Cain). Monday saw blue skies and cool temps and very little wind. Tuesday the clouds rolled in and the storm arrived bringing strong to moderate SE winds and light to moderate snowfall...
Weather Forecast
December goes out with a bang!!!! A very large storm front arrives bringing significant snow fall Tuesday night shifting to heavy rain Wednesday morning.... Things settle Thursday in the eye of the storm and then Friday we head right back into extreme winds and heavy rain again ( this time not even the highest reaches of our peaks will escape this wet one). Wednesday: 5 to 20 cm of snow in the evening followed by a nasty 17 to 100 (yes 100!) mm of rain during the day. Some zones will see this rain taper off in the evening with snow 8-17 cm. Winds will be extreme tapering to strong SE to SW, Temps for 1500 m will range from -2 to +3. Freezing levels from 700 to 2000 m. Thursday: Catch your breath with only a trace of snow or trickle of rain, light variable direction winds, temps for 1500 m 0 to -2.5, freezing level 1000 to 1300 m. Friday: 10 to 20 cm of snow for some zones followed by 40 to 100 mm of rain, winds extreme to strong SE to SW, temps for 1500 m -3 up to +4, freezing level 1100 to 2200 m.
Terrain Advice
If you don't like our current snowpack don't worry its about to get reset by a huge event. Avoid ALL avalanche terrain when the hazard/danger level is HIGH, it's that simple..... Don't fret.. use this time to tune up your gear... add or build those essential items you have been meaning to scrape together but never have the time to... (restock first aid kits, build a repair kit). Practice your first aid skills, read up on the science of snow or rescue skills, you can even practice your avalanche transceiver skills in the backyard with an umbrella. We will all be back out there soon enough.
Snowpack Summary
It was an amazing day out Monday! Nice fresh new powder over a mainly supportive crust with clear blue bird skies. Tuesday the elephant in the room slowly crept in and the storm arrived mid afternoon.
Snowpack Details
- Surface: New snowfall at the start of the storm event that will roll into Wednesday.
- Upper: Low density snow in sheltered, bonding poor to moderate to the crust below with wind effect in exposed zones.
- Mid: Snow from previous storms with some weak layers that are active in tests but not to human triggers.
- Lower: Well settled
Confidence
Moderate - While all will fall apart and confidence is high for wed thurs.. the ? is will there be anything left to avalanche during the storm Friday
Problems
Wet Slabs
New snow and previous storm snow will be saturated by rain which will result in wet slab avalanches, most likely failing on the buried crust layer below the snow that fell Sunday night, possibly even triggering or stepping down to weaknesses found in layers below that crust.
Location; All aspects and elevations
Likelihood of triggering very likely to almost certain to both natural and human triggers
Size one all the way to three.
Likelihood
Expected Size
Loose Wet
Rain saturating the upper snowpack will result in loose wet sloughs.
Location: all elevations and aspects
Likelihood of triggering: Very likely to almost certain to both natural and human triggers
Size one to two.
Likelihood
Expected Size
Storm Slabs
Significant amount of new snow will fall over the next three days which will result in storm snow avalanches.
Location: Alpine and Treeline elevations on all aspects (especially NW to NE where the wind will send even more snow)
Likelihood of triggering: Very likely to almost certain to both natural and human triggers
Size: size one to size three.
Likelihood
Expected Size
Valid until: Dec 31st, 2020 1:00AM
