11 Feb 2021

February 11, 2021

     YESTERDAY:

      Sunrise Wednesday was at 07:31 Hrs. -17 with a 5-10 KPH SE breeze.

      There were some glimpses of blue to the North in the am.

      Was looking like there was a potential to break in the am.

     There were some nice turns to be had.

      Sun teased us most of the am.


     There was some wind deposited snow on North facing slopes.


      Wednesday Feb 10, 2021. 14:00 Hrs. -17 with a 0-5 KPH ESE breeze. -10 in the valley.


      Satellite image from Wednesday afternoon.

     Great temps for making snow. Moist arctic front limited sublimation.

     Arctic front parked over top of Whistler all day. 


Weather Observations for February 11, 2021 taken at 06:00 Hours.

2240 meters      -19, Winds were 20-40 KPH N--Horstman Hut
2180 meters      -19, Winds were 15-20 KPH NNE--Whistler Peak
1860 meters      -23, Winds were   5-15 KPH S --Rendezvous 
1835 meters      -23, Winds were 10-20 KPH E--Round House
1650 meters      -23,  trace in 12 Hrs, trace in 24 Hrs, Base 245 cm --Pig Alley
1570 meters      -22,  trace in 12 Hrs, trace in 24 Hrs, Base 176 cm--Catskinner
  660 meters      -16, Valley Temp, Max temp Yesterday was -8.9, 0.3 mm of precip yesterday.

-23 with a 15 KPH wind brings the wind chill to -33. Dress warm, no exposed skin!!! Getting colder!!!


      As of 07:00 Hrs this am we have clear skies and unlimited visibility. It looks cold!!!


FORECAST:

Sunny weather this am with a Northerly flow aloft. The FL will remain well below surface. Today looks like it may be the coldest. Likely see some cloud development in the afternoon. Friday is looking sunny in the morning with cloudy skies in the afternoon as an upper low moves down the coast. Should see light snow by early Saturday morning with warmer temps (-10), weak front will last until Saturday night. Another weak front pushes through early Sunday am with very light snow and seasonable temps. Guesstimates: 0 cm by Friday am, 1-4 cm by Saturday am, 2-5 cm by Sunday am, 1-4 cm by Monday am.


      GOES IR image from this am.

      Arctic front has reached the coast, perhaps we will have more sun today. Low sliding South.




      Northerly flow aloft.


      Upper low moving down the coast, should see an increase in cloud by Friday afternoon.





       Periods of light snow for Saturday.


      AVALANCHE ACTIVITY:

      Avalanches plaque the Western U.S. & Europe. Article below.                                         Net Pic

      An avalanche hits the village of La Grave, France. Article below.                                Net Pic

      No new avalanche activity observed on Whistler.

      No new avalanches observed on Blackcomb.

AVALANCHE SUMMARY FOR SEA TO SKY AREA:

Avalanche Summary

With cold temperatures gradually robbing the upper snowpack of cohesion, observations from the past few days show a trend away from wind slab releases and toward small loose dry avalanches triggering in steep start zones with skier traffic. That said, a few more small wind slabs were still able to be triggered with ski cutting in the Whistler area on Tuesday.

Notably, a size 3 (very large) persistent slab was remotely triggered (from a distance) by a group of skiers in the McGillivray Pass area (northern South Coast Inland region) on Monday. This occurred on a southwest aspect at 2400 metres. It was described as a hard wind slab formed over the facet layer from late January detailed in our snowpack discussion.

Snowpack Summary

Up to 15 cm of low density snow can be found on the surface in shaded, sheltered areas. In more wind exposed areas this is replaced with a mix of wind-affected surfaces, including wind slabs that are gradually losing cohesion and reactivity under prolonged cold temperatures. A thin recent sun crust may be found right near the surface on solar aspects.

Below this mixed bag of surface conditions, 50-100 cm of settled storm snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1900 m, and a sun crust on south-facing slopes. There could be more than 100 cm on this layer in wind loaded areas. Although this structure is a bit suspect, we have no recent reports of avalanches failing at this interface.

A crust from early December, currently considered dormant, may be found around 200+ cm deep in the snowpack.


     INFORMATION & OBSERVATIONS:

      It looked cold at 07:45 Hrs Wednesday. -16 with a 5-10 KPH North breeze.


      Nice snow on many elevations and aspects.

      Teetering Rock.

     Thin arctic front cloud did not want to go away.

      Very little air movement at tree line on Wednesday.

      Arctic front with limited visibility on Wednesday afternoon.

      Light snow accumulating in trees.


RECENT MIN REPORTS FROM SEA TO SKY:

Trorey Glacier: Feb 9, 2021

Steep Creek S Turn: Feb 10, 2021

Overly Complicated Picnic: Feb 10, 2021


Avalanche Activity in B.C. MIN Reports: Lessons to be learned.

Apex Proper Main Bowl avalanche: Feb 10, 2021

Tunnel Creek Avalanche: Feb 10, 2021

White Rabbit Cornice failure: Feb 10, 2021


VIDEOS:

Powder Picker Feb 10, 2021: David Jones


ARTICLES:

Avalanche hits Village of La Grave: France

23 avalanche fatalities in the U.S. so far this season: CAIC

Fatal avalanches in several states over 7 days mark deadliest period of avalanches in the U.S. since: 1910

Avalanches and climate change: Wasatch Weather Weenies

Slow rescue frustrates families of missing in India avalanche: "It is a Mess"

Avalanches plaque Western U.S., Europe: ExplorersWeb

Himalayan Glacier Disaster highlights Climate Change Risks: Northern India


      Submit your best avalanche photo for a pair of  Goggles Feb 1-28, 2021. Sea to Sky Area.

                                                    Thanks to Volkl Canada for sponsoring.  

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