HEADS UP! HEAVY SNOWFALL AND STRONG WINDS WILL CAUSE THE AVALANCHE DANGER TO RISE QUICKLY TODAY!
The avalanche danger is CONSIDERABLE this morning and will likely reach HIGH on steep, wind drifted slopes that face NW through E as the day progresses. Recent, new, and wind drifted snow threaten to dangerously overload an underlying, weak snowpack and dangerous, natural and human triggered avalanches will grow increasingly more likely throughout the day. Most other terrain at mid and upper elevations will see a rising CONSIDERABLE avalanche danger. Backcountry travelers need to have excellent route finding skills. Travel in avalanche terrain is not recommended.
As new snow accumulates, soft slab avalanches will become increasingly more likely throughout the day with the greatest sensitivity during the periods of highest precipitation. Be on the lookout for sensitive soft slabs on any steep slope once we see about 6" of new snow.
On slopes facing NW through E, fresh deposits of wind drifted snow have formed over top of a dense slab, 2'-3' thick, that exists on a persistent weak layer of loose, sugary facets. Over the past two weeks, these slabs have grown increasingly stubborn to release but to be sure, any avalanche triggered on this weak, faceted layer would be deep and dangerous. With new and wind drifted snow continuing to add stress to this persistent weak layer, we could be approaching the breaking point and steep slopes facing NW through E should be avoided.
Blowing and drifting snow has formed new wind slabs on leeward slopes that face primarily NW through E, but the gusty, erratic behavior of the winds may have deposited snow on a variety of aspects. Look for fresh drifts on the leeward sides of terrain features such as sub ridges, gully walls, and rock outcroppings. Fresh drifts are recognizable by their smooth, rounded appearance, and cracking is a sign of instability. On northerly aspects, wind drifted snow has added stress to older slabs on top of a buried persistent weak layer and dangerous, human triggered avalanches 3'-5' deep are possible. Avoid steep, wind drifted slopes, especially those that face the north side of the compass.
Road Conditions: Expect to find accumulating and drifting snow on the road. Plowing may occurr later in the day.
Grooming: Grooming will be temporarily on hold with continued snow in the forecast and a downed tree that needs to be cleared.
24 Hour Snow 3" 72 Hour Snow 15" Base Depth in Gold Basin 39" Wind SW 20-25 G35 Temp 21F
Gold Basin SNOTEL site (10,000')
Wind Station on Pre Laurel Peak (11,700')
NWS Weather Forecast
Light snowfall began around midnight and intensified around 5:00 a.m. Heavy snow should continue through the day with 8"-12" possible. 20-30 mph southwest winds with gusts to 40 along ridge tops will create widespread blowing and drifting snow. High temps at 10,000' will be in the upper 20's. Snowfall should continue into the evening before tapering off around midnight with another 2"-4" possible after sunset. Winds will back off and shift to the NW and temps will plummet into negative territory. New Year's Day will see cloudy skies and a chance for scattered snow showers, blustery NW winds, and frigid temps in the single digits. Sunday will be cold, clear, and sunny.
Snowpack
Snow totals since Christmas Eve are up around 24" at 2.4" SWE, with 15" of snow and 1.4" of water since Tuesday. Today we're looking to add another 1.0" to 1.5" of water. In addition, nearly continuous wind loading over the past week has deposited deep drifts on to leeward slopes. All of this translates to a significant load being applied to a persistent weak layer of sugary, October facets beneath a slab. This slab ranges from 2'-3' thick on terrain facing NW through E. Stability tests have shown that this persistent weak layer is stubborn to react, but with continued wind loading, and heavy snow forecasted for today, it may just be enough to tip the scales. What is certain is that any avalanche failing on these weak facets would be deep, dangerous, and likely un-survivable.
Dave Garcia and company were up yesterday. Read their observation here.
On Thursday night, UAC forecasters gathered to discuss the upcoming dangerous conditions.
Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.
This forecast is from the U.S. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.
