The weather system that is currently affecting Mt. Washington.
In case you have been living in a windowless cubicle, or perhaps a basement, we’re in the middle of what could be described as a winter storm. The reality is that it is not yet the middle of the storm, more like the start, and furthermore it’s hard to refer to sleet and freezing rain as a winter storm. But whatever it is or whatever you call it, it’s here and it’s going to influence the avalanche and skiing/riding conditions for the coming weekend. At Hermit Lake, we’re waiting for the sleet to turn to snow, but unfortunately that has yet to happen.
In advance of the storm that started today, we’ve had good snow coverage across most of the ravines. In fact, compared to how things have looked the last couple years by mid-April, I’d say we’re in very good shape. While we’ve had some rain this last week, avalanche danger had been able to drop down to Low before the current storm. This surface is currently very frozen and crusty, so underneath whatever falls, the threat of long sliding falls is going to be out there.
Looking at the weather for the weekend, I am sorry to say I see nothing that leads me to believe we’ll see the much-desired sunny spring corn snow fiesta. Instead, we’re looking at cloudy conditions until late Sunday. Snow, sleet, and maybe freezing rain will be the dominant feature tonight, which will affect what happens tomorrow for avalanche danger. If most of the precipitation is snow, and winds wrap to the west as forecasted, we’ll have a difficult time lowering the danger ratings from today’s Considerable. We can hope for the new snow/sleet mixture to bond well to the underlying rain crust, but there is still enough uncertainty in the forecast to take an accurate shot at forecasting how it will play out.
On the one hand, we could get all snow. This would lead to elevated avalanche hazard from westerly winds blowing it into the ravines. On the other hand, we could get sleet capped with freezing rain. The winds would have a hard time loading this stuff into unstable windslab, but even if it’s stable it doesn’t mean the skiing and riding will be good.
So if you are going to come up for the weekend, you should prepare for another shot of winter-like weather. Spring will be on hold for the time being. Be flexible with your plans. The Sherburne is open from top to bottom, and the Tuckerman trail is skinnable from the bottom to the top. If you are sure you want to go above Hermit Lake into steep terrain, bring and ice axe and crampons, at least. And food for thought…read the post I just put into The Pit this afternoon. Personally, I would opt to find another more suitable adventure for tomorrow rather than come to Tucks hoping for something good to ride.
This advisory expires at midnight Friday, April 12, 2013
Tuckerman and Huntington Ravines have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely.
We are starting out the day with Low avalanche danger in all forecast areas. As precipitation accumulates today, the avalanche danger will rise.This will require those venturing into avalanche terrain today to carefully evaluate the snow to determine it’s potential to avalanche. Currently, the forecast is for 1-3″ of snow and sleet accumulation this morning with freezing rain and sleet in the afternoon with mostly snow expected above 4,000′, though there is strong uncertainty in the timing and precipitation types with this storm. That translates to uncertainty in the exact timing of our avalanche forecast. One thing that is consistent is the one half to one inch of total liquid expected out of the storm with enough of it falling as snow between now and Saturday afternoon to allow for a forecast of 6-12″ of frozen precipitation on the ground. Until then, skiers or climbers should expect a mix of precipitation types below Hermit Lake gradually becoming more snow from there to the summit. Skiers should expect and prepare for a hard icy surface beneath the incoming precipitation with along sliding fall hazard to exist before the new snow and sleet begin to create an avalanche threat. Sounds like fun, huh?
By this afternoon we may have a better handle on skiing and climbing conditions for the weekend. It doesn’t look good for anything other than an elevated avalanche danger tomorrow as a west wind will ramp up and further load slopes and gullies with an easterly aspect like the Lip and Center Bowl and Central and Pinnacle Gullies. If the cold air remains in place and prevents too much warm air from affecting precipitation and the winds are right, then our snow fall totals on the Alpine Garden and summit ridges will be more than adequate to create a significant avalanche hazard. Be sure to check our Weekend Update as well as tomorrow morning’s advisory for more details. Ice dams, weakened snowbridges over streams and off trail postholing as well as narrow slots developing in Tuckerman and moats near rock faces are among the hazards which exist today.
The Harvard Cabin is closed for the season; we are no longer issuing Huntington-specific forecasts at the cabin, but will continue posting this version of 5-scale advisories at the cabin. The only camping permitting on the eastern side of Mount Washington is at Hermit Lake Shelters.
Safe travel in avalanche terrain requires training and experience. This advisory 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.
Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or at Hermit Lake Shelters.
Posted 7:55 a.m. 4-12-2013. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856