Monday February 4, 2019
Wind Slab, Loose Dry
Travel & Terrain Advice
Study the potential wind transport of the new low density snow that fell Sunday, over the next few days. With the atypical winds forecast from the N-NW avoid suspect wind loaded pockets/slopes on the S-SE in the alpine and open treeline avoid cross loaded features as well.
The new light low density snow does not have a lot of push to it, but sloughing snow moving around you can be a bit disorienting. Use ski cuts and slough management to reduce these effects.
A few size 1-1.5 slab avalanches were reported from the Mt Cain zone (west bowl) over the weekend. Mt Washington saw numerous small size 1 loose dry sloughs from steep terrain on Sunday in the new low density snow that fell during the day. No reports came in from the Strathcona zone.
Moderate winds from the N-NW forecast for the next few days will have little trouble moving the new light dry snow from Sunday. This transportation will load S-SE slopes in the alpine and open treeline creating potential wind slab avalanche danger. These slabs triggering potential is likely to possible with human activity on these loaded slopes and possible with natural activity up to size 2.
New light dry snow (10 -20 cm) that fell during the COLD snap Sunday has a poor bond to the snow below. It is almost certain that this snow will be easily triggered both naturally and by humans on steep slopes of all aspects and elevations up to size one.
Well spring version 6.0 is done but we can still feel its crust below the new snow.
|Surface||15-35 cm of new snow from Friday and Sundays events, with the latest very light and dry.|
|Upper||The (approx 10 cm) crust that we had all been enjoying..... last week, bridging and limiting any concerns below|
|Mid||20-30 cm of old storm snow over a very thick (20-30 cm) crust (down approx 80 cm) producing only hard results in tests|
Two new snow events (it was about time) with the first falling late Thursday into Friday bonding moderately to the old crust. The second event through the day Sunday during the very cold snap (around -15) dropping about 15-20 cm of very low density powder bonding poor to what ever it fell on. Winds have been mainly light and freezing levels dropped to sea level.
Very little to no new snow for the next three days. The next significant snow is forecast to fall late Wednesday into Thursday. Winds will be a bit different than usual SE to SW, as they will flow from the north/north west .
Monday - no new snow, temps -15 to -6, winds moderate from the N-NW, freezing level 0 sea level.
Tuesday - no new snow, temps 0 to -9, winds moderate to light from the N-NW, freezing level 0 to 900 m.
Wednesday - 0 to a trace of new snow during the day (with light to moderate snow forecast overnight heading into Thursday) temps -3 to -6, winds light NW switching to light SE as the next snow system arrives, freezing level 0 to 700 m.
Posted on Monday February 4, 2019 by Bill Phipps