Avalanche Forecast for Sunday, March 29, 2020

This information was published 03/29/2020 at 7:00 AM.
A new forecast will be issued tomorrow.

NOT THE CURRENT FORECAST

This is an archived avalanche forecast and expired on 03/29/2020 at midnight.


The Bottom Line

On Friday, March 27th, NH Governor Chris Sununu joined other New England states in issuing a stay at home order for the State of NH in an effort to limit the spread of a pandemic. Violating this order potentially spreads the illness through the public, USFS Snow Ranger staff and volunteer rescue teams. Contact with patients could lead to 14 day quarantine for staff and responders. No one plans to have an accident in the mountains. If you do, know that our response will be limited and will require the help of bystanders and other forest visitors. Furthermore, any accident will strain local first responders and hospitals. There are many ways to be outdoors and get needed exercise, backcountry skiing should not be among them now.

New snow, rain and poor visibility are on tap today. The new precipitation will be falling on a mix of wind scoured ice crust near the tops of gullies and above treeline or porous, refrozen but breakable crust in leeward areas. Evaluate weather and terrain carefully. Avalanche danger is MODERATE today. Small human triggered avalanches may become possible in steep terrain. 


Mountain Weather

Yesterday, calm winds, cool temperatures and some cloud cover kept the snow mostly cold and frozen.

Today, mixed precipitation is expected to amount to 1-3”. Temperatures will flirt with the freezing point, with variable amounts of snow, sleet and rain the result. Wind will be from the SE at 15 to 30 mph, increasing to 35 to 50, with gusts up to 65 late. 

Tomorrow, more snow will arrive with up to 4” through the 24 hour period. There is a fair amount of uncertainty on the amount that will fall. Wind will be strong from the southeast around 40-55 mph early in the day. 

Primary Avalanche Problem – Wet Loose

Wet Loose

Aspect/Elevation

Likelihood

Size

Avalanche activity will most likely be limited to wet loose avalanches though it’s possible that soft slabs of snow remain in isolated areas. New snow and any pockets of the older, soft snow may become saturated and more sensitive to a human trigger. Beware of larger avalanches later in the day if heavy rain soaks through to the old ice crust that exists 6-12” down near treeline topouts.

  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.

Forecast Discussion

Ambient temperatures over the past week have flirted with the freezing point at Ravine elevations with solar aspects being more strongly affected. Moist and crusty snow was easily breakable yesterday and thinned from mid boot to shallower near the top of gullies in Tucks with the need for crampons and ice axe required for comfortable passage in most areas. Glide cracks are emerging across the Headwall and ice is turning white and showing signs of loosening its grip on cliffs. Heavy rain late this afternoon will speed the transition to a spring snowpack, open streambeds and further open glide cracks and moats. 

Additional Information

The Sherburne and Gulf of Slides ski trails are snow covered to Pinkham Notch.

The Lion Head Winter Route remains the easiest route to the summit from Pinkham Notch but requires an ice axe, crampons (not just micro-spikes) and possibly a rope. This is a mountaineering route and requires solid skills for a safe, timely ascent.

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. Click here to check it out.

Recent snowpack and avalanche observations can be found here and on Instagram. Your observations help improve our forecast product. Please take a moment and submit a photo or two and a brief description of snow and avalanche information that you gather in the field.

Snow Plot Information

DateHN24HN24W
(SWE)
Density (%)HSTTotalAir TT MaxT MinSkyPrecipComments
04/13/20
06:15
0 CM 0.1 MM0CM206 CM-3.5 C7.5 C-7.0 COvercastRain
04/12/20
06:20
Trace 1.8 MMTrace216 CM-7.0 C-4.0 C-7.0 CFewNo precipitation
04/11/20
06:20
14 CM 23.1 MM 14%62CM222 CM-8.0 C-6.0 C-8.0 COvercastNo precipitation
04/10/20
06:30
53 CM 49.5 MM 12%NC200 CM-6.0 C-2.0 C-6.5 COvercastSnowView
04/09/20
06:25
0 CM 0.0 MM0CM158 CM-1.0 C8.0 C-4.5 CClearNo precipitation

Avalanche Log and Summit Weather

Thank you Mount Washington Observatory for providing daily weather data from the summit of Mount Washington.

DateMax TempMin TempTotal (SWE)24H Snow & IceWind AvgWind Fastest MileFastest Mile DirAvalanche Activity
05/21/2053 F38 F 0.0 in 0.0 in29.4 MPH59 MPH

280 (W)

05/20/2050 F34 F 0.0 in 0.0 in29.4 MPH59 MPH

280 (W)

05/19/2041 F27 F 0.0 in 0.0 in15.3 MPH36 MPH

100 (E)

05/19/2050 F34 F 0.0 in 0.0 in11.4 MPH25 MPH

30 (NNE)

05/18/2045 F30 F 0.0 in 0.0 in14.7 MPH36 MPH

70 (ENE)

05/17/2040 F30 F 0.0 in 0.0 in17 MPH35 MPH

270 (W)

05/16/2037 F28 F .16 in 0.0 in38.8 MPH101 MPH

310 (NW)

05/15/2042 F32 F .95 inTrace 31.5 MPH95 MPH

250 (WSW)

05/14/2035 F19 FTrace 0.1 in42.8 MPH85 MPH

300 (WNW)

05/13/2022 F9 F 0.0 in 0.0 in66.3 MPH98 MPH

300 (WNW)

05/12/2018 F12 F .51 in 3.5 in58.5 MPH100 MPH

310 (NW)

05/11/2034 F18 F .65 in 5.1 in35.1 MPH73 MPH

280 (W)

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.

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 03/29/2020 at 7:00 AM.

Frank Carus
USDA Forest Service
White Mountain National Forest