Yesterday, temperatures hovered in the teens F at high elevations with light wind shifting from N to SW late in the day. This morning, a W wind is blowing at 26mph and should sit there for most of the day, gusting up to 40mph. Temperatures will again linger in the teens F with clouds developing this evening. Making plans for the weekend? Expect a stable weather pattern with a chance of upslope snow showers tonight and tomorrow night that may produce up to an inch at mid and upper elevations each night.
Primary Avalanche Problem – Wind Slab
Soft wind slabs are the main avalanche concern today. These are most likely small in size and can be found near terrain features that can interrupt the flow of wind, such as trees, cliffs, gully walls, or rocks. Firm wind slabs can be found on more open slopes that offer a higher degree of tensile strength bridging the weak layer that can be found under all wind slabs. While firmer wind slabs will be more stubborn to trigger, these will produce larger avalanches as they will be found on larger, connected slopes. Thanks to sunshine yesterday and again today, identifying wind slab (dull, white) vs. ice crust (shiny, reflective) should be easy from afar as can be seen in Huntington yesterday.
What is a Windslab Avalanche?
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
As the MWV IceFest comes into town this weekend, it will be good to keep in mind safe travel with your group, especially since this festival draws lots of climbers to area climbing venues. History has shown climbers tend to treat avalanches more as an objective hazard and are also willing to get in line for the classic climbs. The current avalanche problem can be managed very easily by choosing terrain appropriate for your group and goals for the day. Much of Huntington Ravine has been hit hard by the wind and is unlikely to produce an avalanche big enough to bury someone. Use this to your advantage and be willing to alter plans based on where the crowds are. Avalanche rescue gear is always worth carrying and may be used to help others who made the mistake you avoided.
Be sure to attend the Saturday evening presentations for MWV IceFest for a closer look at avalanche events on Crawford Notch ice climbs and which part of our forecast is specifically geared toward these routes!
The Sherburne and Gulf of Slides ski trails are snow covered to Pinkham Notch. A generally warm winter has left open water in many areas, including water bars and often skiable drainages such as Monroe Brook.
Details on daily snowfall totals, precipitation type, total depth of snow and other information can be found on our page devoted to snow study plot data. Clickhere to check it out.
Recent snowpack and avalanche observations can be foundhere and on Instagram. Your observations help improve our forecast product. Please take a moment andsubmit a photo or two and a brief description of snow and avalanche information that you gather in the field.
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 01/31/2020 at 7:06 AM.
USDA Forest Service
White Mountain National Forest
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