30 Dec 2020

December 30, 2020


      Just before sunrise Tuesday morning.

      Early morning keeners!!                                                                                            Greg Dixon Pic

     Overcast with stratus cloud Tuesday am in the valley.

     A few breaks in the am.

      Some nice light but very brief.

      Snow filled in on the South West side.

     Tuesday 14:00 Hrs. -4 with a 20-30 KPH South wind. -2 in the valley.

      GOES IR mage from the same timeframe.

      More weather on the way.

Weather Observations for December 30, 2020 taken at 06:00 Hours.

2240 meters      -5, Winds were 60-75 KPH ENE--Horstman Hut
2180 meters      -6, Winds were 55-65 KPH ESE--Whistler Peak
1860 meters      -3, Winds were 20-35 KPH S --Rendezvous 
1835 meters      -4, Winds were 15-30 KPH ESE--Round House
1650 meters      -2, 13 cm in 12 Hrs, 13 cm in 24 Hrs, Base 161 cm --Pig Alley
1560 meters      -4, 13 cm in 12 Hrs, 13 cm in 24 Hrs, Base 105 cm--Catskinner
  660 meters      -2, Valley Temp, Max temp Yesterday was -0.9, 2.0 mm of precip yesterday.

      As of 07:00 Hrs this am we have obscured skies, limited visibility and snowing 2 cm/Hr.


A warm front will push through this morning in a strong South West flow aloft. Light to moderate precipitation with a rising FL topping out at around 1200 m. A trailing cold front should bring the FL back down to around 1000 meters by tonight and ease to flurries by early Thursday am. A very weak and short lived ridge will bring unsettled weather for Thursday with mostly cloudy skies and a few sunny breaks. The next front arrives Thursday night into Friday with light to heavy precip, strong winds and a FL hovering in the 1400 m range. More of the same on Saturday with mostly moderate to heavy precip. A break on Sunday with flurries. A series of frontal bands will continue into nearly next week. Guesstimates:14-18 cm by Thursday am, 6-10 cm by Friday am, 25-35 cm by Saturday am, 70-90 cm by Sunday am. 

      GOES IR image from this am.

       Low will send a warm front with a trailing cold front today with light to moderate precip.

       Shortwave ridge will bring unsettled weather for the day light hours of Thursday.

      Strong Pacific front pushing through on Friday, FL will hover around 1400 m.


     An avalanche has killed two snow bikers near Pemberton. Article & MIN report below. MB Pic

       Skier Accidental (Sa) Brandywine Area, MIN report below.                       G.M. Nussbaumer Pic

      Dry loose in Lakeside Bowl from Monday.

      No new avalanches observed at Blackcomb, 1 Sc Sz 1 on Whistler.

From Sea to Sky Advisory:

Avalanche Summary

There was a fatal avalanche in the South Coast Inland region (near the Sea to Sky boundary) north of Pemberton in the Goat Peak area on Monday. This avalanche resulted in two fatalities. It was reported to be a size 2.5 persistent slab avalanche on a west aspect, around 1650 m. The RCMP press release can be viewed here.

A size 2.5 avalanche was triggered on Monday by a skier on Rainbow Mountain, which resulted in a full burial and, thankfully, a successful rescue. The avalanche failed on a 60 cm deep crust and facet layer on a northeast aspect around 1800 m. 

A size 3 persistent slab avalanche was reported on Mount MacBeth on Monday, check out this MIN report for details of this observation.

These avalanches highlight the ongoing potential to trigger persistent weak layers in the snowpack. 

A small (size 1) avalanche was also triggered on Monday by skiers on a north aspect in the Whistler backcountry, most likely in recent storm snow.

Snowpack Summary

There has been up to 40 cm of recent snow in the region, with another 10-15 cm expected during the day on Wednesday. Moderate to strong southwest winds are expected to redistribute this snow, forming storm slabs in lee terrain features.

Two potential concerning weak layers may be present in the snowpack: 

  • The shallower layer, around 60 to 100 cm deep, includes feathery surface hoar crystals. This layer may be found in sheltered terrain features at treeline and lower alpine elevations but has been reported as spotty across the region. 
  • The more widespread weak layer includes sugary faceted grains that overlies a hard melt-freeze crust. This layer ranges in depth from 10 cm to 120 cm due to the wind scouring and loading the snow in different terrain features over the past two weeks. The layer has been reported as being widespread up to around 2000 to 2200 m. 

To date we have mostly seen sporadic avalanche activity on these layers, but they remain possible to trigger where they exist in the mountains.


      Stratus layer flowing in from Pemberton Tuesday am.

      Checking out Upper Disease Ridge.

      A very snowy looking Kadenwood.

      Fitzsimmons Creek

      Fissile Peak


Grizzly Lake, Sa: Dec 28, 2020

Mount Chief Pascal: Dec 28, 2020

Stellar Bowl: Dec 28, 2020

Skier Accidental-Tremor/Trorey: Dec 28, 2020

Matier-Sa: Dec 28, 2020

Round Mountain: Dec 29, 2020

Phalanx/Spearhead Zone: Dec 29, 2020

Railroad Pass-Long Goat-Fatalities : Dec 29, 2020


Avalanche on Cirque du Fer a Cheval: France

Powder Picker Dec 29, 2020: David Jones

Avalanches on Buck Ridge: Montana


Two Snow-Bikers dead after Pemberton Avalanche: Pique

Two SAR calls-one injured man rescued, two snow bikers die in avalanches: Pemberton

Skier escapes slide as weak snow sustains avalanche risk in parts of B.C.: Daily Courier

Be Prepared--Avalanche Rescue Practice Tips: Wild Snow

Storm Bella has created a complicated situation in the Alps: France

WANTED any transceiver either working or not:

$150 reward for trading in on a new Arva Neo Pro at $499
$100 reward for trading in any transceiver in on an Evo 4 at $329 or Evo 5 at $385

Mike Dempsey
Your representative in Canada and the United States for ATMRECYCYCLINGSYSTEMS.COM and VORTEXDEPOLLUTION.COM in Canada

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