Yesterday for most of the day the region saw sustained northeasterly winds 10-20 mph. Sunburst weather station recorded gusts into the 30s and 40s. Although only a trace of new snow fell there was old soft snow available for transport. Look for signs of wind loading in the Alpine. Fresh wind slabs maybe tender on steep, unsupported, leeward slopes. Watch for cracking in the surface snow and stiffer snow over softer snow. Although wind slabs are likely to be shallow, they could be more dangerous if they were to step-down and trigger a large slab that breaks in the MLK buried surface hoar. On steep, protected slopes watch for sluffing.
CORNICES: Cornices are looming large in some of the Alpine terrain. Give them an extra wide berth as they often break farther back than expected.
Note the increased wind speeds during the day on Sunburst yesterday. This was enough to move snow in the Alpine.
As time goes on the likelihood of triggering a large avalanche on the MLK buried surface hoar has decreased. Over the last few days many people have been pushing into steeper terrain without incident. However, don’t forget the lingering concern that this is the kind of avalanche problem where several tracks may be on a slope before someone finds a trigger point and the whole slope avalanches. The MLK buried surface hoar that is roughly 1-3′ deep has been responsible for 13 human triggered avalanches since January 26th. The last one was Wednesday February 6th on Eddies. On that day snowpack tests were pointing toward a stabilizing weak layer and then the 2′-3′ deep avalanche was triggered remotely from the ridge on a steep, unsupported slope.
What to keep in mind today:
1- This weak layer is widespread in the region and seems to be particularly suspect between 2000′-2500′ due to a melt-freeze crust associated with it.
2- Use safe travel protocol. Expose only one person at a time (this includes paying attention to other groups in the area), watch partners, stop in safe zones and be rescue ready.
3- Wind loaded steep features, large connected and unsupported slopes are the most suspect. As always, one can simply avoid high consequence terrain and stick to slopes under 35 degrees with nothing steeper above to avoid the issue.
The MLK buried surface hoar over a melt-freeze crust in a snow pit on Repeat Offender, 2-7-19.
Glide cracks continue to creep open and are scattered across the region. The last glide crack to release into an avalanche was over a week ago in the Summit zone just north of Manitoba. Glide cracks are unpredictable, not associated with human triggers, and can release without warning at any time. Look out for glide cracks and limit exposure under them.
Lipps glide cracks threaten the skin track and ski terrain, 2-8-19.
Yesterday: Mostly cloudy skies with very light snow flurries. Winds were northeasterly 10-20 mph with gusts into the 40s. Temperatures were in the 20Fs to 30Fs. Overnight temperatures dropped slightly and winds shifted to the west and eased off, averaging 5-10 mph gusting into the teens.
Today: Partly cloudy skies with some valley fog becoming mostly cloudy tonight. There is a chance of snow showers overnight, 1-3″. Winds will be light and westerly and temperatures will be in the 20Fs and 30Fs.
Tomorrow: Skies are forecast to clear in the early morning and become mostly sunny. Winds will be light and westerly and temperatures will be in the 20Fs to low 30Fs. There is a slight cooling trend with sunshine on tap for most of the week. The next chance for snow looks to be over the weekend.
*The Seattle Ridge anemometer (wind sensor) was destroyed. We have a replacement on the way and it should be operational by mid February.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||29||0||0||57|
|Summit Lake (1400′)||25||0||0||25|
|Alyeska Mid (1700′)||28||trace||0.03||50|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||26||*N/A||*N/A||*N/A|