Wayne Flann Avalanche Blog: January 13, 2021

YESTERDAY:

Tuesday January 12, 2021. Sunrise 08:07 Hrs. -0.5 Deg C with a 15-30 KPH ESE wind.

Walked on at 09:15 Hrs.

Snow in the trees but warm and moist in the valley.

Early skers get the turns.

Good turns until the FL went to 1860 meters by 09:00 Hrs. It was -1 by 15:00 Hrs.

Anticipation!! Elevating FL, blowing snow. Did open up in the afternoon. Only alpine lift to open!

Why wait when there are lots of turns to be had.

Tuesday 14:00 Hrs. -1 with a 10-25 KPH ENE wind. +1 in the valley. Where did everyone go?

GOES image from the same timeframe. More moisture on the way.

Pineapple Expresses makes for a very wet valley.

Had that warm wet look in the afternoon.

Weather Observations for January 13, 2021 taken at 06:00 Hours.

2240 meters -9, Winds were 70-100 KPH SE--Horstman Hut

2180 meters -8, Winds were 60-85 KPH ESE--Whistler Peak
1860 meters -6, Winds were 20-50 KPH S --Rendezvous

1835 meters -6, Winds were 50-90 KPH S--Round House

1650 meters -4, 16 cm in 12 Hrs, 18 cm in 24 Hrs, Base 258 cm --Pig Alley (34.2 mm)
1560 meters -4, 15 cm in 12 Hrs, 16 cm in 24 Hrs, Base 175 cm--Catskinner (21.7 mm)

660 meters +1, Valley Temp, Max temp Yesterday was +1.5, 29.1 mm of precip yesterday.

Max gust last night at 2240 m was 164 KPH at 01:15 hrs.

Max gust last night at 2180 m was 180 KPH at 01:45 hrs.

As of 07:00 Hrs this am we have obscured skies, limited visibility and snowing 1 cm/hr.

FORECAST:

Upper trough exiting the area this morning with lingering showers in a North Westerly flow aloft. A weak ridge begins to build this afternoon with unsettled weather. The FL will drop back down to surface sometime this am. Mostly cloudy Thursday morning with some sunny breaks in the afternoon with warm air moving in from the high pressure to our South. A short wave trough may push through Thursday night into early Friday morning with some light precip, short lived with unsettled weather by Friday morning and ridge rebuilding by the afternoon with a mix of sun and cloud. Dry but overcast on Saturday. Guesstimates: 1-3 cm by Thursday am, 2-4 cm by Friday am, 2-6 cm by Saturday am.

GOES IR image from this am.

Upper trough will shift East and ridge will build in for unsettled weather by this afternoon.

Very warm air moving into the area on Thursday. Unsettled weather. Weak front Thursday night.

Weak front early Friday am, then unsettled.

Quick Short Wave Trough on Friday am.

AVALANCHE ACTIVITY:

4 people have been killed after avalanche buries their vehicle, Pakistan. Article below. Net Pic

Avalanche control on Whistler produced Sz 1-2 Xe Xc Xl Sc soft slabs and cornice results.

AC on Blackcomb produced Sz 1-2 ssl Xe Xl Sc. Warmed up and Na Sz 1-2.

From the Sea to Sky Avalanche Bulletin:

Avalanche Summary

On Tuesday there were no new avalanche reports at the time of publishing.

On Monday reports from avalanche control using explosives saw up to size 2 slab avalanches on slopes below cornice failures.

Natural avalanche activity is expected to continue on Wednesday.

A large (size 3) avalanche was remotely triggered by skiers on Cowboy Ridge near Whistler on Saturday. 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 on Thursday; check out this MIN for more info and photos.

These avalanches are clear evidence that the weak layers described in the Snowpack Summary are still triggerable by riders and the consequence of being caught would be high.

Snowpack Summary

Up to 40 cm of new snow blanketed the region by mid-day Tuesday with more in the forecast by Wednesday morning. New and reactive storm and wind slabs will exist. Below treeline the upper snowpack may see a firm crust as freezing levels drop.

The snowpack is currently quite complex. The recent storm snow just buried yet another surface hoar layer down around 30-40 cm in the sheltered treeline and below treeline locations. 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 Whistler and Pemberton.

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: