Friday December 27, 2019

Sunday December 29, 2019
Saturday December 28, 2019
Friday December 27, 2019
Confidence: Moderate - Many field days, but the loss of weather station data for the western island (Strathcona) leaves a gap in the knowledge.

Main Concerns

Loose Wet, Wind Slab, Loose Dry - view Avalanche Problems for detailed information.

Travel & Terrain Advice

Deep powder loaded slopes are very tempting, but remember loose dry avalanches can be dangerous especially if they are associated with terrain traps, natural features that magnify their depth (gullies) or increase the chance of trauma (pushed off a cliff or into a band of trees). Start with small consequence slopes first to test the zone you want to play on before committing to the line you are truly craving.

Avoid wind loaded slopes (NW - NE) in the alpine and treeline elevation bands. Significant winds late Thursday and more forecast for Saturday will create a dangerous wind slab avalanche problem

Watch for the forecast warm up later on in the day Saturday. Warm temps and high freezing levels will make the snow pack more sensitive to triggering avalanches. Plan to be off and away from avalanche prone slopes if you note this warming trend. The warm up is forecast to be more significant in the eastern (Mt Washington) and western (Strathcona) regions. Up north (Cain) things stay a bit cooler but stay alert and observant as well.

In your excitement to shred the Gnar… (since we are all starved for snow play and the snow is soooo nice) REMEMBER the snow is not very deep yet. Many rocks, stumps and open creek holes are waiting for you, especially at lower elevations. Go slow out there…if you can.

Avalanche Summary

Some small loose dry avalanche activity was reported with human triggering (ski and snowmobile) on steep treeline elevation slopes up to size 1 over the past three days. No natural activity was reported but most likely loose dry slides did occur in the alpine up to size 2.

Avalanche Problems

Loose Wet

If the forecast is correct (and I hope it is not) watch for a warming trend and even some rain late Saturday (esp in the west and east regions) If this does occur it could quickly destabilise our nice soft snow-pack and result in loose wet avalanches. These avalanches would occur in the below treeline and treeline elevation bands on all aspects. Due to current soft upper snow pack conditions triggering would very likely result naturally and would be almost certain with human activity up to size 2. Keep your spidey senses tuned to the possibility of this warm up.

Wind Slab

Significant winds from the SW/SE late Thursday and another blast forecast for Saturday will load lee NE/NW slopes in the alpine, treeline and on cross-loaded features. These wind slabs may possibly be triggered naturally and will likely trigger with human activity. They have the potential to be up to size 2 to 2.5

Loose Dry

Light new snow may result in loose dry avalanches at alpine and treeline elevation bands on all aspects (not enough snow and a lot of anchoring trees rocks, bushes at below treeline). These avalanches will very likely trigger with human activity and may occur naturally as well up to size 1.5

Snowpack Summary

Well its some amazing powder (certainly lighter than we are used to for the island)…. if only it was deeper!!! The total snow-pack is approx 40-70 cm below treeline 70-130 cm at treeline 130-180 cm in the alpine

Snowpack Details

Surfacelight dry powder, some wind effect in open and higher zones
Upperdry snow slowly getting stiffer the deeper you get
Mida couple layers of interest but they seam to be healing and becoming less of a concern (buried surface hoar)
Lowera weak layer right near the ground (basal facets under a thin crust)

Past Weather

Around 24 cm of new light snow has fallen over the past three days. Significant winds from the SW to SE late Thursday redistributed a lot of snow on to NE and NW slopes in the alpine and treeline.

Weather Forecast

A more gentle day Friday followed by another moderate snow fall high wind event Saturday. Late Saturday a unfortunate warm up with near 0 temps, high freezing levels and maybe even a bit of rain (east and west more likely to get it while north might miss out) followed by some light to moderate new snow Sunday.

Friday - 2 to 4 cm of new snow, light SW winds, temps -1 to -4, freezing level ranging from 400 to 1000 m

Saturday - 5 to 10 cm of new snow (with possible extra 5 cm of snow or 5 mm of rain depending on freezing levels and temps) strong SE winds, temps -3 rising to potential +1, freezing levels 900 to 1200 m

Sunday - 5-10 cm of new snow, moderate SE dropping to light variable direction winds, temps -1 to -3, freezing levels 800 to 1000 m

Posted on Friday December 27, 2019 by Bill Phipps

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