Wayne Flann Avalanche Blog: December 9, 2020

YESTERDAY:

Early Tuesday am, variable conditions.

Moist clouds at all elevations.

Tuesday Dec 8, 2020. 14:00 Hrs. -1 with a 0-5 KPH South breeze. +2 in the valley.

From same timeframe as above image.

System is slowly sliding South East.

Skiing improved as the day progressed but wet where the snow was best.

Weather Observations for December 9, 2020 taken at 06:00 Hours.

2240 meters -5, Winds were 25-30 KPH E--Horstman Hut

2180 meters -5, Winds were 20-30 KPH SSW--Whistler Peak
1860 meters -4, Winds were 10-20 KPH ESE --Rendezvous

1835 meters -4, Winds were 10-25 KPH S--Round House

1650 meters -2, 2 cm in 12 Hrs, 7? cm in 24 Hrs, Base 97 cm --Pig Alley
1560 meters -1, 1 cm in 12 Hrs, 3 cm in 24 Hrs, Base 62 cm--Catskinner

660 meters +2, Valley Temp, Max temp Yesterday was +2.8, 21.9 mm of precip yesterday.

As of 07:00 Hrs this am we have clear skies and unlimited visibility. Valley fog and mid Mtn cloud.

FORECAST:

A dry day is expected with unsettled weather in a Westerly flow aloft. Mostly cloudy in the valley with sunny skies in the alpine and chance of some isolated flurries by this afternoon in the lower cloud layer. Valley cloud will likely lift this am. The FL should hover in the 1200 meter range dropping to 800 meters tonight. A very weak disturbance should pass through Thursday afternoon with some periods of light precipitation. Depending on what model you like to use some are calling for unsettled weather but looks like it will be mostly cloudy. A low off the coast may bring some periods of light precipitation on Friday. We will hopefully see some more snow by late Saturday with seasonable temperatures. There is uncertainty in the models for the next few days. Guesstimates: 0-trace above 1000 m by Thursday am, trace-1 cm above 800 meters by Friday am, 2-4 cm by Saturday am.

GOES IR image from this am.

Unsettled weather with cooler temps for today.

Unsettled for Thursday but feel like it may be cloudy with some moisture.

May see more unsettled weather Friday but looks like the low may send some moisture our way.

AVALANCHE ACTIVITY:

Avalanche mitigation produced Sz 1-2 ssls entraining wet loose. Xe Xc

Blackcomb Bowl Sz 2 Debris Sc. Na up to Sz 2 were also observed.

Moist snow with some powder burns.

From Sea to Sky Avalanche Advisory:

On Tuesday, storm slab avalanches to size 2 were triggered by explosives, and evidence of a natural avalanche cycle to size 2 was also reported.

On Monday afternoon, small size 1 loose and low density slab avalanches failed naturally and with skier traffic as snow began to accumulate and load ridgetops.

INFORMATION & OBSERVATIONS:

Alpine remained closed on Tuesday on the Blackcomb Side. Snowing lightly at 13:00 Hrs.