Avalanche Forecast for Tuesday, April 7, 2020
This information was published 04/07/2020 at 8:46 AM.
The Bottom Line
Surface snow stability at mid elevations will decrease today as temperatures rise above freezing leading to the chance for sluff (wet-loose) avalanches on steep slopes. Watch for wet snow at the snow surface as an indicator that this hazard is increasing. Clouds may limit snow surface warming, while direct sun will exacerbate this hazard on south aspects. Avalanche danger today is LOW.
Yesterday the summit reached a high of 23F under sunny skies and a west wind. Flurries very early in the day brought .3” of snow on the summit while Harvard Cabin received no measurable precipitation. High temperature at Harvard Cabin was 44F.
Today, temperatures will again reach the lower 20s F, with NW wind 25-40 mph. Partly sunny/clouds may limit the effects of solar radiation, and a chance for snow flurries are expected to result in no accumulation.
Tomorrow, high cloud cover with temperatures rising to the upper 20sF. NW wind at 15-30mph. Clouds increase tomorrow (Wednesday) night with up to 1” snow possible. Looking further, up to 12” of snow possible late Thursday into Friday.
Primary Avalanche Problem – Wet Loose
Wet Loose avalanches will be possible as the snow surface warms above freezing. Snow surface warming may happen at all aspects as the temperatures rise, though direct sun on the snow surface will increase the likelihood and size at those locations. These “sluff” avalanches should be small, and found mostly on the steepest terrain. Watch for pinwheels and rollerballs as signs of increasing likelihood. Cloud cover today will be the largest determining factor contributing to this avalanche problem today.
What is a Wet Loose Avalanche?
Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Snowpack changes look to be subtle for the next two days. Significant storm Thursday into Friday brings increasing avalanche danger to be aware of. As of today, NWS is calling for all/mostly snow.
Safe travel in avalanche terrain requires training and experience. This forecast is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
Avalanche danger may change when actual weather differs from the higher summits forecast.
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.
Posted 04/07/2020 at 8:46 AM.
USDA Forest Service
White Mountain National Forest