21 Apr 2021

April 21, 2021

     YESTERDAY:

      08:00 Hrs Tuesday April 20, 2021. +9 Deg C.  +4 at 1650 m. + 3 at 1835 m. 0 at 2180 m.

     10:00 Hrs. + 12 Deg C at 660 m. +7 at 1650 m. +5 at 1835 m. +3 at 2180 m.


         12:00 Hrs. +15 Deg C at 660 m. +10 at 1650 m. +8 at 1835 m. +4 at 2180 m.

      Rethel Mountain < click for explanation.


     14:00 Hrs. +18 Deg C at 660 m. +12 at 1650 m. +9 at 1835 m. + 4 at 2180 m.

      Satellite image from same timeframe as above image.

     16:00 Hrs. + 18 Deg C at 660 m. +11 at 1650 m. +8 at 1835 m. +4 at 2180 m.


      False Face


Weather Observations for April 21, 2021 taken at 06:00 Hours.

2180 meters     +2, Winds were 15-20 KPH S--Whistler Peak 
1835 meters     +3, Winds were   5-10 KPH SE--Round House
1650 meters     +1,  0 cm in 12 Hrs, 0 cm in 24 Hrs, Base 242 cm --Pig Alley
  660 meters        0, Valley Temp, Max temp Yesterday was +20.6, 0.0 mm of precip yesterday.


      Sunrise, 06:06 Hrs. Clear skies and unlimited visibility. High scattered clouds to the NE.


FORECAST:

High pressure, and a trough passing by will bring a mix of sun and cloud for today in a North Easterly flow aloft. The FL will spike at around 2500 metes today dropping to just above surface tonight. Ridge strengthens for Thursday with another sunny day. Unsettled early Friday morning with an increase in cloud cover by the afternoon and the arrival of a front Friday evening, with periods of light precip into Saturday as an upper low pushes through. A weak upper trough will bring unsettled weather for Sunday with some showers and a mix of sun and cloud. Back to a more spring like pattern. Guesstimates: 0 cm by Thursday am, 0 cm by Friday am, 2-5 mm by Saturday am, 11 mm by Sunday am, 2-6 mm by Monday am.


      GOES Satellite image from this am.



      A mix of sun and cloud for today as a cold front moves down through the interior sending cloud.





      North-North Easterly flow aloft.

      High rebounds for Thursday with sunny skies.




        Low slides into the area by Friday night. Cooler temps.




      AVALANCHE ACTIVITY:

      Digging out the essential highway after a wet avalanche in Northern India.


From Sea to Sky Avalanche Advisory:

Avalanche Summary

Over the weekend, multiple large to very large wet slab avalanches were observed near Whistler, size 2-4. Many of these involved the full depth of the snowpack, running to valley bottom.

 

Solar triggered wet loose avalanches have been reported each day over the past week up to size 2.5. There have also been a number of cornice failures reported over the past week.

Snowpack Summary

A slight dip in overnight freezing levels combined with radiant cooling has formed a melt-freeze crust from 1700-2200 m. Reports indicate that this crust is approximately 15 cm thick but will likely break down quickly with solar radiation and freezing levels through the roof. At lower elevations the snowpack is isothermal. Steep north aspects above 2200 m and higher may still hold dry wintery snow.

Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight.



      INFORMATION & OBSERVATIONS:

      08:00 Hrs Tuesday. +5 Deg C. High yesteday was + 23.5 Deg C. Ideal golf weather.

      West Cirque

      West Cirque later in the day, different perspective.

      Another Blue Bird day.

     Full Moon will be on April 26, 2021-- Supermoon

 




FROM SEA TO SKY MIN REPORTS:

No new MIN reports as of 07:00 Hrs.



VIDEOS:

Wet Slab avalanches released with explosives: Montana


ARTICLES:

Preliminary report on Deadly Alaskan Heli-Skiing Accident: NTSB

Warns of avalanche danger when the sun warms the snow: Sweden

Can extreme melt destabilize ice sheets: Science Daily

Listening to avalanches half a state away: Alaska

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