Backcountry Avalanche Forecast Presidential Range This product is expired and archived Issued: Monday, February 1, 2021 - 7:18AM Expires: Tuesday, February 2, 2021 - 12:00AM Author: Frank Carus THE BOTTOM LINE LOW avalanche danger exists throughout the forecast area, though the potential for small avalanches of wind drifted snow remains in isolated areas at mid and upper elevations. Natural and human triggered avalanches are unlikely. Hard, smooth snow exists on many other aspects. Crampons and an ice axe will increase your security in those areas. Avalanche danger is expected to increase significantly overnight and tomorrow as a winter storm brings significant snowfall and wind to the Presidential range. Natural avalanche activity will become likely in many areas with very dangerous avalanche conditions developing. Avalanche Danger Monday, February 1, 2021 - Low, all elevations Tuesday, February 2, 2021 - High Upper and Mid elevations, Considerable Low elevations Avalanche Problem #1 Wind Slab N -> E Upper and Mid Elevations Unlikely Small (D1) Left Gully and the variations of Chute along with north facing gullies in Huntington are examples of the isolated areas where wind slabs exist. The smooth, hollow sounding slabs are easy to identify and are generally worth avoiding due to low skiing quality and postholing on foot if not due to the elevated avalanche risk. Forecast Discussion A mix of snow surfaces exist at mid and upper elevations preceding the incoming Nor’easter. Most of our middle and upper elevation areas have a wind scoured, mostly smooth surface. This snow surface was the result of the 157 mph wind last weekend. It is very dense and mostly smooth and will make for a perfect bed surface for avalanches to run. South facing aspects saw direct and intense sun but snow did not warm at middle and upper elevations. Much of the western aspect of the range has limited snow coverage but there are plenty of areas large enough to produce a large (D2) to very large (D3) avalanche with the incoming snow. Think Oakes Gulf and the Ammo as falling into the latter category. Webster Gullies and slabs will also see quite a bit of snow and if not wind loading at least the potential for an upside snowpack as snow switches to sleet or freezing rain for a period of time tomorrow. The key variables to watch in this storm beyond the obvious snowfall totals is the wind speed and direction, especially the backing winds and their potential load south facing aspects and crossload others. Looking further ahead, upslope snow and northwest winds on Wednesday and Thursday may continue to increase the risk of natural avalanches depending on snow density and availability for wind transport. Watch the hourly observations here for “blowing snow”. As long as that appears, the potential for natural avalanches will exist. February 2 - This product is expired and archived This was in effect during a fatality believed to have occurred on Feb 2 The forecast for Feb 1 was LOW but the outlook for Feb 2 was as described below (High) Avalanche Warning ISSUED Tuesday, February 2, 2021 - 8:30AM EXPIRES Wednesday, February 3, 2021 - 7:30AM What The avalanche danger is increasing throughout the day. Very dangerous avalanche conditions are actively developing on and below steep slopes in the mountains. Natural avalanche activity due to heavy snow and wind is very likely and travel in avalanche terrain is not recommended. When In effect from Tuesday, February 2, 2021 - 8:30AM to Wednesday, February 3, 2021 - 7:30AM Where The Presidential Range avalanche forecast area, which includes steep, open terrain in the mountains that are bounded by US Rt 2, US Rt 302, and NH Rt 16. Avalanche Warning criteria may also be met in other areas outside those forecast by the avalanche center. Impacts An ongoing winter storm is bringing heavy snowfall and wind, creating unstable conditions in many areas in the backcountry over the next 24 hours. Precautionary/Preparedness Actions Backcountry travelers should plan on rapidly changing conditions. Travel in avalanche terrain is not recommended. Backcountry Avalanche Forecast Presidential Range Issued Tuesday, February 2, 2021 - 7:36AM Expires Wednesday, February 3, 2021 - 12:00AM Author Jeff Fongemie THE BOTTOM LINE The chance for avalanches will increase through the morning rising to HIGH, as continued snowfall and wind drifting create very dangerous avalanche conditions. Natural and human triggered avalanches are almost certain. Travel in avalanche terrain is not recommended Avalanche Danger Tuesday, February 2, 2021 Upper Elevation: High (4) Middle Elevation: High (4) Lower Elevation: Considerable (3) Outlook for Wednesday, February 3, 2021 Considerable (3) Considerable (3) Moderate (2) Avalanche Problem #1 Wind Slab All Elevations All Aspects except NE-E Likelihood: Almost Certain Size: Small (D1) to Large (D2) Strong wind and snow today will rapidly build wind slabs that will be reactive or even touchy at mid and upper elevations. While the size of the new slabs has some level of uncertainty due to differences in forecast snow totals, even the lesser forecast is enough to create a large avalanche. Visibility will be challenged today due to blowing snow, drifting and loading will be difficult to predict due to cross loading behind rock buttresses, and natural avalanches will be likely in many areas. Travel in avalanche terrain is not recommended. Forecast Discussion The snowpack that existed prior to today’s storm will play the role of bed surface with no significant widespread weak layers present. Soft snow could be found in isolated areas and may contribute to the size of the debris flow if entrained into an avalanche, but for the most part the hard existing bed surface will act as the sliding surface for avalanche activity today. The chances of an avalanche stepping down deep into the existing snowpack is limited, however this should not be a factor in your decision making today. With 7” overnight, and up to 12-13” today, new snow combined with wind is sufficient to make travel in avalanche terrain dangerous. Please Remember: 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.