Wayne Flann Avalanche Blog: January 14, 2021

YESTERDAY:

Busy Wednesday morning.

. Breaks in the morning.

Green in the valley.

Challenging visibility when Glacier Express first opened. Especially with the crust below 1900 m.

Variable skiing surfaces depending on elevation and aspect.

There were some turns to be had.

Wednesday Jan 13, 2021. -7 with a 15-25 KPH SW wind. +2 in the valley.

GOES image from same timeframe as above.

Challenging conditions but another nice day.

Weather Observations for January 14, 2021 taken at 06:00 Hours.

2240 meters -8, Winds were 15-20 KPH SE--Horstman Hut

2180 meters -8, Winds were 10-20 KPH NNW--Whistler Peak
1860 meters -9, Winds were 0-5 KPH S--Rendezvous

1835 meters -6, Winds were 5-10 KPH SE--Round House

1650 meters -7, 0 cm in 12 Hrs, 0 cm in 24 Hrs, Base 248 cm --Pig Alley
1570 meters -6, 0 cm in 12 Hrs, trace in 24 Hrs, Base 169 cm--Catskinner

660 meters -2, Valley Temp, Max temp Yesterday was +3.0, no data mm of precip yesterday.

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

FORECAST:

A weak short lived high will bring unsettled weather for today in a Westerly flow aloft. Cloudy this am with sunny breaks later in the am, increased cloud cover near the end of the day with a weak short wave trough pushing through tonite into early Friday in a South West flow aloft and strong winds. The FL may rise to above 2000 meters today as the system draws warm air from the south. Hoping it hovers around 1600 meters, dropping to 1000 meters tonight. Unsettled weather Friday with weak ridging, bringing a mix of sun and cloud. Saturday is looking cloudy and gray with cooler temperatures and another weak front arriving Saturday night into Sunday. Weather will dry out next week! Guesstimates: 8-12 cm by Friday morning, 0 cm by Saturday am, 8-12 cm by Sunday am.

GOES IR image this am.

High pushes North around the low drawing warm air from the South.

Low to our North will slowly slide down the coast with cold front arriving tonight.

Weak front in the morning with unsettled weather again by the afternoon.

Stuck between the low and high, cloudy and dry Saturday.

AVALANCHE ACTIVITY:

Avalanche control on Whistler produced Sz 2 out of Glacier East Cornice Xe.

Result under Tram on Whistler. Xe Xc produced mostly Sz 1-1.5 slabs, a few Sz 2.

The weekend Chutes Wednesday afternoon.

AC on Blackcomb produced Sz 1-2 storm slabs Xe Xc Xt. Widespread Na cycle up to Sz 3.

Three Blind Mice Blackcomb Glacier. Natural cycle observed on both mountains. TS Photo

Surfs Up. 2-Sz 2 Xt 1-Sz 2.5 Xy. Tony Sittlinger Photo

Wet loose Na on Hot Rocks.

Roof avalanches occurred during the storm as well.

Cowboy Ridge Na during the storm. Image taken Wednesday afternoon.

Side view of Cowboy Ridge Slide.

Avalanche ran to the flats.

From the Sea to Sky Advisory:

Avalanche Summary

On Wednesday, there were reports of numerous natural slab avalanches up to size 3 above 2000 m from N-NW aspects. Most of these were triggered within the storm slab and stepped down to deeper persistent weak layers. I suspect more observations will be made with good visibility on Wednesday and Thursday.

Last Saturday, a large (size 3) avalanche was remotely triggered by skiers on Cowboy Ridge near Whistler. The avalanche occurred on a north to northwest aspect at around 1900 m. The crown ranged reached up to 200 cm and was approximately 200 m wide. Check out this MIN for photos and more information. A similar avalanche was remotely triggered by skiers on a nearby westerly slope a few days before; check out this MIN for more info and photos.

The weak layers described in the Snowpack Summary may continue to lurk post-storm. If triggered, the consequence of being caught would be high.

Snowpack Summary

Up to 50 cm of recent storm snow blanketed the region and buried another surface hoar layer in wind-sheltered terrain. The new snow combined with strong to extreme wind by Wednesday morning has formed new and reactive storm and wind slabs. Below 1900 m the upper snowpack may see a firm melt-freeze crust.

The snowpack is currently quite complex. Deeper in the snowpack numerous layers of surface hoar may be found down 100 to 200 cm. This is the depth of the greatest concern, where surface hoar or sugary faceted grains may sit above a hard melt-freeze crust from early December. Last weekend, several large natural and human-triggered avalanches on this layer occurred, with the hot spots being around the Whistler backcountry.

Near the base of the snowpack, there may be faceted grains above a crust from early-November, which was identified as the failure layer in recent sporadic large avalanche releases.

INFORMATION & OBSERVATIONS: