12 Feb 2017

February 12, 2017


    AVALANCHE ACTIVITY:

    Fatal avalanche near the summit of Brianconnais, France. Story in article section.           Net Pic

   A ski tourer has been killed in an avalanche in the Stura Valley, Italy. Story below.               Net Pic

    Avalanche control yesterday produced some Sz 1-1.5 storm slabs Xh (heli) with 2 Kg shots.

    February 11--Sz 2.5 Sa, no involvement with associated Sz 2 Sy(50). E aspect 1900m immediately lee of 
     ridge top. Suspect FCxr below 170203 WSL. Northwest of Whistler


    YESTERDAY:

    Early Saturday morning, February 11, 2017.

    Looking North in the morning.

    Unsettled mid day.

    Eventually more cloud appeared.

    End of day the clouds had thickened.



Weather Observations for February 12, 2017: taken at 06:00 Hours.

2240 meters    -11, Winds were 20-35 KPH SE--Horstman Hut 
2180 meters      -9, Winds were 25-35 KPH S  --Whistler Peak
1860 meters      -9, Winds were 15-20 KPH SE--Rendevous
1835 meters      -7, Winds were 10-25 KPH S   --Roundhouse
1650 meters      -7, trace of new snow, trace in 24 hrs, 264 cm Base, RH 87%  --Pig Alley
1550 meters      -8, trace of new snow, trace in 24 hrs, 195 cm Base, RH 91%  --Catskinner 
  660 meters      -2, Valley Temp, Max Temp Yesterday was +2.9, 0.0 mm of Precip recorded yest


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



FORECAST:

An upper ridge is building to our South, but we can expect mostly cloudy skies this morning becoming unsettled with a Westerly flow aloft. The FL today will slowly rise to about 1400 meters by tonight, and the flow will switch to Southerly. The ridge will strengthen Monday for sunny conditions with an associated warm air mass. The FL on Monday could reach 2800 meters.Tuesday will be unsettled and become cloudier later in the day as the next front moves onshore. The FL will hover in the 2100 meter range. A front moves into the area Tuesday night into Wednesday bringing wet windy weather and high snow levels. There are some inconsistencies in the models so hard to accurately forecast the FL. Looks like it will be cool in the morning rising to 2300 meters by Wednesday evening. Another cooler front pushes through Thursday with a slowly decreasing FL, starting at around 1600 meters dropping to 800 meters by Thursday night. At this time Friday looks unsettled but that's a ways off. No guesstimates today, wet snow by Wednesday morning in the alpine.


    GOES IR image from this am. Cloudy this morning, unsettled by the afternoon.

    Today's image, unsettled with some breaks this afternoon.

   High strengthens for Monday.

   Sunny for Tuesday, high will shift Eastward Tuesday night allowing a warm Southwesterly flow.

   Warm Westerly flow with rising FL for Wednesday.

    Low will hopefully bring some cooler temperatures for Thursday.

    Lows move in Tuesday night.




OBSERVATIONS &  INFORMATION:

    February 11, 2017  Blowdown Area-Duffy Lake                                                     Jeff Van Driel Image


Skied near Blowdown peak today and got up to 2000m under deep, slightly upside down trailbreaking conditions with ski pen being 30-40cm and foot pen 80cm. Sheltered areas are skiing well regardless although the forests have been treebombed. We had broken skies with increasing cloud in the afternoon, light to moderate NE winds at -7. 
50-80cm sits on cold previous surface with minor density changes. In exposed areas there is a 30-40cm windslab creating punchy, upside down, variable conditions. Sheltered areas are also slightly upside down. We experienced isolated settlements below treeline and at treeline. The February 8 interface is down 50-80cm and February 3 is down 90-110cm. 
Testpit  at 1930m on a NW aspect with a snow depth of 280cm produced moderate resistant planar and sudden collapse windslab results down 30-40cm and moderate to hard resistant planar results on the February 8 storm interface down 80cm. 

There was evidence of the storm avalanche cycle to size 2.5 but no new avalanches observed. 
Primary concerns are storm slab and wind slab triggering potential possible to likely up to size 2.5. There is also a small possibility for an avalanche to step down to the December or November layers in shallower faceted features. 

Have fun out there! Cheers Jeff

                                                                                                                                                            Jeff Van Driel Image


February 11 at 4:02pm




Took some friends out for a walk to St. marks this morning. Tons of avvy debris out there, looks like just about everything that could have released before St. marks in the last cycle did, save for one or two paths. One was at least a size 2. Typical north shore (light)dust-on-(bulletproof)crust, in most places. I didn't get a great photo, but almost every aspect had a layer of beautiful 3cm long needle like hoar frost.

    North Shore Mountains.                                                                         Matt Barry Image

    Nester's weather station.

   Some blue at around noon Saturday.

   Clouds and blue mid day.


ARTICLES:

Fatal avalanche in the Hautes Alps: France

Ski Tourer killed in an avalanche in Stura Valley, Cunea: Italy

Skier triggered avalanche closes Snowking: Jackson Hole

Can snowbikes and sleds co-exist: Mountain Sledder

An eye for Snow Safety, a heart for winter: Frank Coffey

Avalanche fears in Western Japan with no let-up in heavy snow: Cold Pressure System

Tree well death at 49 Degrees North Ski Area: Washington State 

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