Wayne Flann Avalanche Blog: December 17, 2020

YESTERDAY:

Snowing at 1000 meters Wednesday am.

Lots of snow in the trees at 1200 meters.

Pretty good visibility in the morning mid mountain.

Tricky light and dense powder made for some challenging turns on Horstman Glacier..

Wednesday December 16, 2020. 14:00 Hrs. -2 with a 15-35 KPH ESE wind. +2 in the valley.

Satellite image from the same time frame.

Weather Observations for December 17, 2020 taken at 06:00 Hours.

2240 meters -7, Winds were 30-60 KPH SE--Horstman Hut

2180 meters -6, Winds were 50-60 KPH E--Whistler Peak
1860 meters -4, Winds were 10-15 KPH WSW --Rendezvous

1835 meters -4, Winds were 15-30 KPH E--Round House

1650 meters -3, 11 cm in 12 Hrs, 12 cm in 24 Hrs, Base 118 cm --Pig Alley
1560 meters -3, 11 cm in 12 Hrs, 12 cm in 24 Hrs, Base 77 cm--Catskinner

660 meters +1, Valley Temp, Max temp Yesterday was +2.8 5.7 mm of precip yesterday.

As of 07:00 Hrs this am we have overcast skies and unlimited visibility. Snowing very lightly.

FORECAST:

A weak upper trough will push through today with some lingering showers this morning in a North Westerly flow aloft. Drying trend this morning into this afternoon with a chance of a sunny break sometime in the pm. The FL will continue to hover in the 1000 meter range. Another front moves onshore tonight with light precip becoming moderate by Friday afternoon with a wet windy warm front. This front will ease by early Saturday morning with another front arriving in the afternoon. Depending on the model Saturday is supposed to be the big day, but it could slide South of our area which may be a good thing with the forecasted precip amounts. More on that in tomorrow's post. Weakening front for Sunday with drier weather by Monday and sun by Tuesday. Guesstimates: 2-6 cm by Friday morning, 20-35 cm by Saturday morning above 1000 meters, 15-20 cm by Sunday morning above 1200 meters, 4-6 cm by Monday morning.

GOES IR image from this am.

Weak upper trough with a drying trend.

Front on Friday with wet windy warm weather. High still giving us warmer temps.

More of the same on Saturday, looks a bit warmer.

Bit of a moist atmospheric river which hopefully drifts South.

AVALANCHE ACTIVITY:

Sz 2 from Hanging Lake, Remote Trigger. Dec 16 MIN Report below. Peter Anowicki Pic

Avalanche control produced some Sz 2-2.5 Xe Xc on Whistler Wednesday.

Not great visibility out of the ski area boundary.

AC on Blackcomb-- Sz 2 on Regulator Xe.

Xy on Regulator Low, Sz 2.

From Sea to Sky Avalanche Advisory:

Early reports from Wednesday indicate varied reactivity on a buried crust layer and include an explosive controlled large avalanches (size 2) on a ridge top feature near treeline. Elsewhere avalanches were small with average crown depths of 5-15cm deep.

On Tuesday there reports of numerous small avalanches (size 1-1.5) that were triggered natural, with ski-cutting and with explosives. More reactivity was noted at treeline below ridges. There were limited alpine observations due to stormy weather. However, natural and human triggered avalanches remain likely with the forecast new snow and strong to extreme southern winds.

INFORMATION & OBSERVATIONS: