Wayne Flann Avalanche Blog: March 23, 2021

YESTERDAY:

Monday sunrise was at 07:10 Hrs. -7 with a 15-25 KPH SW wind.

By 09:00 Hrs mid mountain cloud over the valley.

Unsettled Monday am.

Another awesome day.

. Nice snow on North Facing slopes.

Fissile.

Isolated convective flurries in the afternoon.

Convective cloud development in the afternoon.

Just after sunset Monday evening.

Weather Observations for March 23, 2021 taken at 06:00 Hours.

2240 meters -10, Winds were 30-40 KPH S--Horstman Hut

2180 meters -9, Winds were 25-35 KPH SSW--Whistler Peak
1860 meters -6, Winds were 15-20 KPH SE --Rendezvous

1835 meters -5, Winds were 10-15 KPH S--Round House

1650 meters -8, 0 cm in 12 Hrs, 0 cm in 24 Hrs, Base 284 cm --Pig Alley
1570 meters -7, 0 cm in 12 Hrs, 0 cm in 24 Hrs, Base 201 cm--Catskinner

660 meters -5, Valley Temp, Max temp Yesterday was +8.0, 0.4 mm of precip yesterday.

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

FORECAST:

Ridge of high pressure will bring a mix of sun and cloud in a Northerly flow aloft this morning. Cloudy skies can be expected later this am as the ridge slowly moves South and the low sends cloud our way. The FL will spike at around 1000 meters dropping back down to surface tonight. Weak frontal band arrives around midnight with light precip into Wednesday morning. Around noon the precip will diminish with cloudy weather, with a chance of a brief break in the afternoon. Ridge rebuilds for Thursday with a mix of sun and cloud. Ridge brings sunny weather into Saturday. Next snow will happen on Sunday. Guesstimates: 8-12 cm by Wednesday am, 0 cm Thursday--Sunday. Possibly 15-20 cm by Monday.

GOES IR image from this am.

High and low duking it out. High shifts South today allowing cloud to move in from the North.

North-North Westerly flow aloft.

Low pushes a cold front through Wednesday am, short lived with overcast skies in its wake.

Ridge rebuilds for Thursday with a mix of sun and cloud. Seasonal temps.

. Ridge rebuilds Thursday, strengthening on Friday.

AVALANCHE ACTIVITY:

Natural cornice drops releasing slab. Bryce Anderson Image

Cornice releases on Decker. Bryce Anderson Image

Decker Steve Whittall Image

Avalanche mitigation on Whistler produced Sz 1.5 slabs Xe Sc. Sz 2 cornice releases Xe Xc.

Cornice control on Flute.

Avalanche control on Blackcomb produced Sz 1.5 slabs Xe Sc Xc. Sz 1 wet loose in the pm.

Cornice control with slab release on Sunset and 5-0.

Slab release on Stupid West from cornice drop.

Cornice control on the Stupids.

Sz 1 Slab out of Ladies First.

Older slab on Fissile.

Wet Loose on Lakeside Traverse.

Pin wheeling on solar aspects.

Above Bony Basin.

From Sea to Sky avalanche advisory:

Avalanche Summary

Avalanche reports during Sunday's storm were limited to a few small (size 1) storm slab avalanches, primarily on wind affected slopes.

Snowpack Summary

Recent snow is settling but may still be blown around in open terrain by westerly wind. Stormy weather since Thursday has delivered about 30 cm of snow to the Whistler area and closer to 50 cm further west and south. This snow sits above a widespread crust, with the exception of high north-facing terrain. Observations suggest the snow has bonded well to these old interfaces. There are currently no concerning weak layers in the snowpack, 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:

Ridge building in from the North West early Monday am.