December 20, 2022

      AVALANCHE ACTIVITY:

     Na slab avalanches in the Bridger's, MT.  2022/12/19. Click> GNFAC Report.  C Von Avis Pic

      Na Sz 2 from Gunnison Area, CO. 2022/12/18. Click> CAIC Report.           Zach Kinler Pic

      Snowmobile Accidental, Roundy Basin, UT. 2022/12/18. Click> UAC Report.    Jear/Gordon Pic

      Fracture line from avalanche that buried a skier in Wyoming.  Article below. BTAC Pic

      Skier carried 457 meters in above avalanche. 2022/12/16. Click> BTAC Report.      BTAC Pic

   

       No new avalanches observed on Whistler Monday. Sz 1 soft slabs forming in lee terrain.

     No new avalanches observed on Blackcomb.

      WEATHER YESTERDAY:

      Sunrise Monday was at 08:07 Hrs. -20 Deg C with a 30-45 KPH South wind at 2280 m.

      Broken clouds 09:00 Hrs in the valley. -19 Deg C at 660 m.

      Monday December 19, 2022. 12:45 Hrs. -17 Deg C with a 10-20 KPH NNW wind at 1835 m.

      Some breaks to the NW at around 13:00 Hrs.

     Monday afternoon, precipitation gone south but cloud stuck around all day.

      Distant holes but overcast for most of the day. Arctic Boundary prevailed over the high.

     Sun set was at 16:11 Hrs Monday. -18 Deg C with a 35-45 KPH SSW wind at 2280 m.

Weather Observations for December 21, 2022 taken at 06:00 Hours.

2280 meters     -14, Winds were 35-45 KPH SE--Horstman Hut

2180 meters     -13, Winds were 30-40 KPH SW-Whistler Peak

1860 meters     -11, Winds were 10-20 KPH S-Rendezvous  

1835 meters     -11, Winds were 10-20 KPH SE--Round House

1650 meters     -15, 6 cm in 12 Hrs, 6 cm in 24 Hrs. Base 114 cm--Pig Alley

1570 meters     -15, 5 cm in 12 Hrs, 5 cm in 24 Hrs. Base  62 cm--Catskinner

  660 meters     -19, Valley Temp, No data from the Environment Canada Site.

Wind chill at 2280 m with a 40 KPH wind= -26. 

       06:00 Hrs 1650 m. ?5 cm with a base of 114 cm. 3.9 mm in the precipitation gauge.

      As of 07:00 Hrs this am we have overcast skies, variable visibility and it is snowing lightly at 2280 m.

FORECAST:

Still model disagreement so difficult to get an accurate forecast. An upper trough will bring some light snow to Whistler today in a North Westerly flow aloft. Low level Southerly flow. Periods of light snow with cold temperatures. Still very close to the edge of the Arctic Boundary. Most of the precipitation from the convergence zone will happen South of Whistler. Arctic high pushes onto the coast with a mix of sun and cloud for Wednesday. A dry day with no precipitation as the upper ridge slides in. Thursday is looking dry and overcast. Front arrives on Friday with warmer temperatures (FL 1500m?) and some precipitation. May be interesting when the moisture first meets the cold air. Could get a trowal but more on that as we get closer. Still some model disagreement so time will tell. Moderate precipitation with rising freezing levels for Saturday (1700m?). Guesstimates: 2-4 cm by Wednesday am, 0-trace by Thursday am, 0-3 cm by Friday am, 8-12 cm by Saturday am above 1000 m, 20-40 cm by Sunday am above 1500 m.

 

      That is a large area of high pressures.

       Goes 17 ABI Image 2022/12/20. 05:00 Hrs.

          Arctic Boundary still in our zone. Overcast and cold. Light snow. Upper trough to the East.

      Some snow for today, still just on the edge of the Arctic High. Most of the precip is South.

     Westerly-Northwesterly flow aloft.

      German model (ICON) calling for most of the precipitation to be South of our zone.

      Boundary pushes a bit more to the West Wednesday. May see some sunny breaks. So close.

      Less cloud from the boundary, mix of sun and cloud. May see more sun! Dry.

            Some push back from the low Thursday. Overcast, slightly warmer. Dry.

      Overcast Thursday.

      Low begins to push back, warmer on Friday. Periods of light snow.

     Snow Friday with more precipitation on the way. 

       Moderate precipitation Saturday, Freezing level rising.

      INFORMATION & OBSERVATIONS:

      08:00 Hrs Monday, mostly overcast. -18 Deg C with a 10-20 KPH South wind at 1860 m.

      Clouds were dissipating by 09:00 Hrs. But the Arctic Boundary won out in the end.

      Pumping out snow lower Blackcomb Monday am. Some water vapour is sublimating.

      Man made Stratus cloud from snow making on Whistler.

      Southerly flow at 1500 m moving man made cloud from snowmaking in Creekside.

    Sublimation<click in snow making. Article on the ethics of making fake snow. Click>Complicated

     14:30 Hours, moderate outflow on Green Lake. Low in the valley of ? Weather Station off line.

FROM AVALANCHE CANADA: 

Travel and Terrain Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Sea to Sky Advisory available top right side of side bar.

LOCAL MIN REPORTS:

AST Refresher Seymour: Dec 19, 2022

Hurley: Dec 19, 2022

Blower on Pauls Ridge: Dec 18, 2022

Goat Mountain: Dec 18, 2022

SHORT CLIPS:

Not much snow: Speed Kiting

Deep Snow: Dog needs a snorkel

Sporty Air: Splat

Terrain Trap: UTAvy

ARTICLES:

Alpha Angle--How far can the avalanche go: WildSnow 

Updated report on the avalanche on Combe de Plans: France

Dad of two dead after avalanche on Swiss Mountain buried him alive: ANANOVA

Avalanche victim rescued by Teton SAR last Dec 16, 2022: Wyoming

Three people caught, 1 injured in an avalanche on La Grave: France

May have to use google translator!

A skier was swept away, injured by an avalanche in Sierre-Chevalier: France

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