Wayne Flann Avalanche Blog: March 22, 2021

YESTERDAY:

Sunrise Sunday was at 07:12 Hrs. -7 with a 15-45 KPH SE Wind.

Snowing lightly at the base Sunday for first lift.

Flat light but decent visibility in the early am.

Thin cloud cover in the am.

Brief break on the Backside of Whistler.

There were some good turns to be had.

Being close to rocks and trees was where it was at!!

Mid mountain cloud layer gave limited visibility.

Snowing and blowing on top of Blackcomb as well.

Where were all the people?

Sunday March 21, 2021. 14:00 Hrs. -5 with a 25-60 KPH SE wind. +2 in the valley.

Satellite image from same timeframe as above image.

19:00 Hrs -6 with a 25-50 KPH ESE wind.

Weather Observations for March 22, 2021 taken at 06:00 Hours.

2240 meters -9, Winds were 25-30 KPH SW--Horstman Hut

2180 meters -9, Winds were 35-45 KPH SW--Whistler Peak
1860 meters -6, Winds were 10-15 KPH S --Rendezvous

1835 meters -7, Winds were 20-40 KPH SSW--Round House

1650 meters -5, 4 cm in 12 Hrs, 4 cm in 24 Hrs, Base 289 cm --Pig Alley
1570 meters -5, 3 cm in 12 Hrs, 3 cm in 24 Hrs, Base 206 cm--Catskinner

660 meters 0, Valley Temp, Max temp Yesterday was +2.1, 1.4 mm of precip yesterday.

My forecast did not work out so well yesterday, most of the precip went South. 1.4 mm recorded at Nesters while Squamish received 17.8 mm at the airport.

As of 07:00 Hrs this am we have obscured skies and limited visibility. Snowing very lightly.

FORECAST:

A weak broad upper trough will bring unsettled weather early this am in a North Westerly flow aloft. A ridge of high pressure will push in by the afternoon with more sun than cloud, with sunny weather later in the afternoon. There is a chance of some convective flurries in the transition period as well. The FL will hover in the 800-1000 meter range dropping to surface tonight. Unsettled weather for Tuesday morning with an increase in cloud cover as the next front moves into the area for Early Wednesday am. Light precip for Wednesday morning with an overcast drying trend by the afternoon. The ridge rebuilds for Thursday with a mix of sun and cloud. The unsettled pattern will last into Saturday with an increase in cloud Saturday afternoon as the next frontal band arrives for Sunday. Guesstimates: 0-trace by Tuesday am, 4-8 cm by Wednesday am, 2-4 cm by Thursday am, 0 cm by Friday am.

. GOES IR image from this am.

Broad upper trough for this am, high will continue to push East.

North-North Westerly flow aloft.

Ridge pushing in with a Low to the North sending some cloud our way.

Low moves in Tuesday night with precip for early Wednesday am.

. Low will bring light precip for Wednesday am.

AVALANCHE ACTIVITY:

A cornice collapse/avalanche has killed a snowmobiler in California. Article below. SAC Image

Huge avalanche buries skier in Austria. Article below. Net Pic

Numerous avalanche rescues in Austria in the past few days. Articles below.. Net Pic

On Blackcomb a few Sz 1 Sc soft slabs.

On Whistler some Sz 1 Sc in steep lee terrain.

Old powder burns above Franz's Meadow.

From Sea to Sky avalanche advisory:

Avalanche Summary

Storm slabs were actively growing throughout the day on Sunday and will continue to grow overnight. While we do not yet have any field reports at the time of publishing, it is likely some of these slabs were becoming reactive later in the day. Some natural avalanche activity is possible overnight, but then as the weather clears on Monday the main concern will be human triggered slabs in the top 20-40 cm of snow.

On Saturday there were a few reports of small size 1 storm slab avalanches from the previous storm as well as some large explosive triggered cornice falls.

Snowpack Summary

Sunday's storm will deliver 15 cm of fresh snow around Whistler and up to 40 cm further west and south. Strong southwest wind will form extra deep deposits at upper elevations. This will bring recent storm totals to 40-80 cm, which sits above a widespread melt-freeze crust (except on high elevation northerly aspects). Recent observations suggest the snow has bonded well to these old interfaces. The lower snowpack is well bonded, although a spotty early season facet layer deep in the snowpack could return as a problem later in the season.

Remember that cornices along ridgelines are large at this time of year and always have the possibility of failing naturally or from the weight of a human.

INFORMATION & OBSERVATIONS:

Cornices continue to grow.