29 Dec 2020

December 29, 2020

      YESTERDAY:

      Sunrise Monday morning was at 08:11 Hrs. -6 with a 0-5 KPH variable breeze. -2 in the valley.

      Stratus clouds above the valley were migrating South.

      Great snow conditions.

      Blackcomb Mountain.

      Wedge Peak.

      Nice sunset Monday evening.


Weather Observations for December 29, 2020 taken at 06:00 Hours.

2240 meters      -5, Winds were 30-60 KPH SE--Horstman Hut
2180 meters      -5, Winds were 50-60 KPH E--Whistler Peak
1860 meters      -4, Winds were 10-15 KPH WSW --Rendezvous 
1835 meters      -2, Winds were 15-30 KPH E--Round House
1650 meters      -6, 0 cm in 12 Hrs, 0 cm in 24 Hrs, Base 152 cm --Pig Alley
1560 meters      -5, 0 cm in 12 Hrs, 0 cm in 24 Hrs,   Base 95 cm--Catskinner
  660 meters      -5, Valley Temp, Max temp Yesterday was +1.8, 1.5 mm of precip yesterday.


      As of 07:00 Hrs this am we have broken cloud and unlimited visibility.



FORECAST:

Upper level ridge exiting the area today in a Northwest flow aloft. Should see an increase in cloud cover as the next front arrives later this afternoon in a Westerly flow aloft. We can expect steady light precip into Wednesday easing to Showers by early Thursday am. Cloudy dry weather for Thursday before a vigorous front arrives Thursday night into Friday. We can expect windy weather Friday into Saturday with moderate to heavy precip. Guesstimates: 10-15 cm by Wednesday am, 8-12 cm by Thursday am, 2-6 cm by Friday am, 20-35 cm by Saturday am, 50-70 cm by Sunday am. 


     GOES IR image from this am.


      Low will spread cloud into the area today with light precip by tonight.





   

      Front for Wednesday in a Westerly flow aloft.





        Low moves down the coast with overcast skies for Thursday. Front arrives Thursday night.


      AVALANCHE ACTIVITY:

      Sz 2.5 Sa (skier accidental) full burial, no injuries on lower Rainbow Shoulder Monday morning.

      Sled assisted skiing, likely ran on Dec 9 crust. 

 
      Six people dug out subject quickly, cleared airway and he walked out of hole. 1.5-2 m burial.


      Sz 2.5 on Macbeth. MIN report below. Point release initiated slab.                Thomas White Pic


      Loose dry on solar aspects Monday afternoon.

      Loose dry on East aspects Monday morning.

     Avalanche observations for WB-Some Sz 1 Xe Xc. Sz 1 dry loose on steep solar aspects.

From SEA to Sky Avalanche Advisory:

Avalanche Summary

A large (size 2.5) avalanche was triggered on Monday by a snowmobiler on Rainbow mountain in alpine terrain, which resulted in a full burial and, thankfully, a successful rescue. The avalanche failed on a layer 60 cm deep. At this time the nature of the failure plane is unknown, but it is reasonable to assume it failed on one of the two weak layers discussed in the snowpack section. This avalanche points to 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

15-30 cm of recent snow has been redistributed by strong south to east winds, depositing deep pockets of storm slab into 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.

The remainder of the snowpack is well-settled.


      INFORMATION & OBSERVATIONS:

     Great colours Monday morning at sunrise.

     Awesome snow quality.

      Lots of wind distributed snow.

      Rainbow mountain.

     Wind effect on Ipsoot Peak.

      Full moon is tonight. Looked pretty full Monday night. Cold Moon

      Very low pressure system will bring a potent storm for this weekend.



LOCAL AVALANCHE CANADA MIN REPORTS:

Macbeth Sz 2.5: Dec 28, 2020

Callaghan: Dec 28, 2020

Cayoosh: Dec 28, 2020

Cloudburst: Dec 28, 2020

Rainbow Mtn-Gin Peak: Dec 28, 2020

Elephant Lakes: Dec 28, 2020

Spearhead Glacier: Dec 28, 2020


VIDEOS:

Powder Picker Dec 28, 2020: David Jones


ARTICLES:

Death toll from avalanche in SE Turkey rises to 2: Hakkari

Avalanche danger at considerable in Idaho and Wyoming: KPVI News

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