26 Dec 2020

December 26, 2020

      YESTERDAY:

      Sunrise was at 08:10 Christmas Day. -4 with a 25-55 KPH East wind. -5 in the valley.

     Snowing Christmas morning.

      Snow conditions were better in the am. Warmed up in the afternoon.

     Flat light but nice snow in the alpine.

      Friday Dec 25, 2020. 14:00 Hrs. -1 with a 15-30 KPH SE wind. -3 in the valley.

      Goes image from same timeframe as above.



Weather Observations for December 26, 2020 taken at 06:00 Hours.

2240 meters      -6, Winds were 40-55 KPH SE--Horstman Hut
2180 meters      -5, Winds were 50-60 KPH E--Whistler Peak
1860 meters      -3, Winds were 15-30 KPH SE --Rendezvous 
1835 meters      -3, Winds were 15-35 KPH E--Round House
1650 meters      -1,  8 cm in 12 Hrs, 14 cm in 24 Hrs, Base 152 cm --Pig Alley
1560 meters      -2,  5 cm in 12 Hrs, 11 cm in 24 Hrs,   Base 92 cm--Catskinner
  660 meters      -2, Valley Temp, Max temp Yesterday was -2.6, 4.4 mm of precip yesterday.


     As of 07:00 Hrs this am we have obscured skies, limited visibility and snowing



FORECAST:

An upper trough will bring periods of light precip in a South Westerly-Westerly flow aloft. The FL may rise to around 1200 meters then drop back down to surface tonight. Unsettled Sunday with the potential for periods of light precip. Ridge builds by late Monday morning with some sun expected in the afternoon. Unsettled Tuesday with a mix of sun and cloud with a weak front arriving Tuesday night. A series of weak fronts for mid week into the weekend. Looks like we may see some more active fronts by next weekend. Guesstimates: 8-12 cm by Sunday am, 4-8 cm by Monday am, trace-1 cm by Tuesday am.


     GOES IR image from this am.

      Weak upper trough will bring periods of light snow for today.





       Unsettled Sunday, mostly cloudy with some flurries.





      Ridge builds for Monday with sunny breaks and some cloud in the mix.

    Ridge builds for Monday.

      AVALANCHE ACTIVITY:

      Two climbers killed, two injured in an avalanche in Iran. Article below.                            Net Pic

     Many Sz 1 Sc on Whistler yesterday. Mostly steep NW aspects soft storm slabs.

     On Blackcomb a few Sz 1 Sc storm slabs.  

From the Sea to Sky Advisory:

Avalanche Summary

Numerous wind slab avalanches were reported this week, triggered naturally and by riders at treeline and alpine elevations. Check out these MINs for a few examples: herehere and here.

A few large avalanches have been observed over the past week, running on buried weak layers (described in snowpack summary). Most occurred on north to east aspects in the alpine. A size 2.5 reported Thursday from a coastal glaciated area west of the Squamish river. It was on a southeast aspect, 100 m wide with crown depth 40-80 cm deep.

Snowpack Summary

5-10 cm of new snow is forecast to fall through the day Saturday, bringing storm totals to 15-25 cm. The new snow sits over hard wind slabs and wind scoured surfaces in exposed terrain, and a melt-freeze crust on solar aspects at upper elevations.

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:

     Drifting snow in 7Th Heaven yesterday am.




      Wind effect in Opal Bowl.

      Nice job on keeping people spread out.

      It looked warm in the afternoon.

      Had to shut the guns down above 700 meters.


LOCAL AVALANCHE CANADA MIN REPORTS:

X-Mas Gully, Mt Strachan: Dec 25, 2020

Chief Pascal: Dec 25, 2020


VIDEOS:

An unstable snowpack, & remotely triggered avalanches in Colorado: CAIC


ARTICLES:

Two climbers killed , two injured in an avalanche in: Iran

Tehran avalanche death toll reaches 8: Tehran Times

Avalanche fatality near the Col du Galibier: France

XMas storm causes avalanche at upstate New York Ski Resort: Catskill Mountains

High avalanche risk in the Pyrenees: France


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