Wayne Flann Avalanche Blog: December 21, 2020

Winter has officially Arrived.

YESTERDAY:

After arriving at 07:45 hrs we were looking at another 5 minutes before uploading.

Power flurries in the am.

Fresh snow brings out the crowds.

Great snow below treeline.

Some breaks just before noon.

Sunday Dec 20, 2020. 14:00 Hrs. -4 with a 30-50 KPH SW wind. +4 in the valley.

Satellite image from same timeframe.

Weather Observations for December 21, 2020 taken at 06:00 Hours.

2240 meters -6, Winds were 30-60 KPH E--Horstman Hut

2180 meters -8, Winds were 50-60 KPH E--Whistler Peak
1860 meters -7, Winds were 10-15 KPH WSW --Rendezvous

1835 meters -6, Winds were 15-30 KPH E--Round House

1650 meters -6, 3 cm in 12 Hrs, 3 cm in 24 Hrs, Base 145 cm --Pig Alley
1560 meters -6, 2 cm in 12 Hrs, 2 cm in 24 Hrs, Base 90 cm--Catskinner

660 meters 0, Valley Temp, Max temp Yesterday was +4.1, 3.8 mm of precip yesterday.

As of 07:00 Hrs this am we have overcast skies, variable visibility, and snowing lightly.

FORECAST:

An upper trough is in the region with a warm front arriving this am in a South Westerly flow aloft. We can expect periods of light precipitation as the system moves South of the area with the FL dropping below surface later in the day. An upper ridge will move into the area early Tuesday am with some lingering cloud and sunny periods in a Northerly flow aloft. The ridge will be the dominant feature until Christmas day when a weak front arrives. Guesstimates: 14-18 cm by Tuesday am, 0 cm by Wednesday am, 0 cm by Thursday am, 0 cm by Friday am, 2-6 cm by Saturday am.

GOES IR image from this am.

Low will bring light precip for today with a FL dropping below surface.

High pressure for tomorrow with mostly sunny skies and some lingering cloud. Cooler temps.

High pressure for Wednesday with some cloud and warmer temps from the warm onshore flow.

AVALANCHE ACTIVITY:

An avalanche has killed 2 backcountry skiers SE of Ophir Pass, CO. Article below. CAIC Pic

Glide avalanche on Nordic Ski Jump, Callaghan. MIN report below.

Buried surface hoar at tree line very touchy, Miller Ridge. Mtn conditions report in article section.

Avalanche control on Blackcomb produced Sz 1 soft slabs Xe.

Avalanche control on Whistler produced Sz 1.5-2 Xe Sa

From Sea to Sky Avalanche Summary:

A few large avalanches were triggered on the buried weak layers described in the snowpack summary on Saturday. They were triggered using explosives as well as by riders. They occurred on northerly aspect in alpine terrain (2100 m) and were generally 30 to 50 cm deep.

Otherwise, small to large (size 1 to 2) storm and wind slab avalanches were triggered by riders and explosives on Friday to Sunday. They generally occurred at treeline and alpine elevations on northerly terrain features and within the top 50 cm of the snowpack.

INFORMATION & OBSERVATIONS:

Wind affected snow with some dense powder in the alpine.