Overnight, temperatures remained above freezing at 3,800’ and up. Warm temperatures such as these which will contribute to the melting that creates the wet avalanche concerns that exist today. The safest and likely, most fun skiing and riding will be on shady aspects due to the sloppy and unsupportable snow in the sun. Human triggered wet loose avalanches are likely on most aspects and may grow large in isolated areas. Free flowing melt-water in the snow may help trigger a large slab on one of the crusts beneath the upper snowpack. Avalanche danger today is MODERATE today.
Field time in Tucks yesterday revealed that water was slow to percolate into the wind slabs that formed on Thursday. The 2-3cm of wet snow on the surface yesterday has likely grown much thicker due to warm temperatures overnight. As more water flows into the snow, bonds between grains will loosen and melt. This avalanche problem will not be widespread but is potentially the most destructive.
Warm temperatures last night did not allow the refreeze needed to create a supportable layer of corn snow. The sloppy surface snow will move underfoot and possibly carry you. Be careful in steep terrain where falls have consequences.
Snow certainly warmed yesterday but not to the point that wet slabs became a big concern. That seems likely to change on sunny aspects today as sunshine and overnight temperatures above freezing lead to deeper penetration of heat into the snowpack. The reflector oven in the glacial cirque of Tuckerman Ravine exacerbated this warming yesterday with runs on Boott Spur like Duchess and Hillman’s Highway remaining cooler. In those locations the ice crust nearest the surface had not broken down yet as it had in other sunny aspects in the Bowl. “Loud skiing” on crusty snow in Left Gully will likely change to soft and enjoyable skiing today with reduced concerns for sluffing and wet slabs. If you are venturing deeper into the backcountry, be sure to test slopes for these wet avalanche types. Skier control is a factor in heavily used areas like Tucks but more remote locations are more likely to have larger avalanche problems. Reduced skier traffic this week will allow both avalanche types to grow larger in size as snow sits undisturbed.
The warm winter and low snowfall totals have made exiting the bowl on ski challenging already. One of the holes in the Little Headwall could be particularly difficult to escape if you are unlucky enough to fall in. Yesterday, it was about 3’ across but increasing stream volume this week will lead to holes like this becoming larger. Be sure to have a look from the courtyard at Hermit Lake before committing to that route. The holes aren’t necessarily obvious from above.
Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at MWAC. Help create a more accurate avalanche forecast by submitting your observations here.
Listen to the weekly MWAC Outreach Podcast provided by Ski The Whites. Discussions include snowpack information, weekend outlook, and general avalanche related info.
Our next free online event is coming up Thursday, March 25 @ 7PM -Opportunity and Cost - with Jake Risch. A Free Zoom Webinar.
The Harvard Cabin is open for camping only with no entry allowed inside the cabin. There is no access to the breezeway at HoJos.
Please Remember:
For more information contact the US Forest Service Snow Rangers, AMC visitor services staff at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or seasonally at the Harvard Cabin (generally December 1 through March 31). The Mount Washington Ski Patrol is also available on spring weekends.
