A Wet Storm and an Arctic Freeze.

The first substantial Nor’easter screamed through our region in the 36 hours before Thanksgiving.  A brief shot of snow was followed by substantial icing at the upper elevations and then heavy rain.  Total water for the event was between 2.4″ (6cm) and 2.6″ (6.6cm) of melt depending on elevation.  Ravine temperatures hovered in the mid to high 40’sF for a good part of the rain event before the freefall of the mercury began locking up the remaining snowpack.  Reviewing the pictures of Tuckerman that were posted on 11/27 will give you a good idea where existing snowfields exist, albeit smaller due to melting.  Rain and warm temperatures hit these snowfields and areas of water ice pretty hard.  What is left are a handful of small snowfields that will act as the bed surface for potential future avalanches when new snow is load on them.  These isolated areas are now very hard and icy making it tough for new loading to bond well.  New snow on these icy hard surfaces could cause instabilities to keep your eyes open for but they cover so few locations we have not yet begun a general advisory.

Of all the terrain we assess mid winter we are only talking about +/- 2-3% of snowfield coverage right now. With that said some of these are sporadically spread through areas where ice climbers have historically chosen as routes through the Tuckerman Headwall and Lip.  A climber paying attention even just a little bit will note many options to avoid new snow pockets when choosing a line. Climbers should also consider the plummeting temperatures rapidly refreezing melt and rain water.  Use some extra caution in the days following this freeze up and expect quite variable conditions.    Expect many areas of ice to be detached, a mix of wet-yet brittle, and thin.

The topics I mentioned in the last posting on 11/24 still hold as true as additional things to keep in mind.  “The classic early season problems are usually found in Tuckerman’s Left Gully, Chute and numerous shelves and benches in the Center Headwall.  In Huntington, common locations have historically been found at the base of popular early season routes like Pinnacle and Odell.  Could instability be found in other locations? Of course, but these are where we see the majority of the early season developments.

  • As we progress towards the solstice daylight is waning.  A headlamp could become your best friend in the event of an injury or a longer than expected day.
  • Warm sun will undoubtedly make an appearance here and there loosening thin early season ice from the Ravine cliffs.  Be cautious when moving through or travelling below these locations.
  • Be sure to check current weather forecasts at the Mount Washington Observatory, posted at the Pinkham and Crawford Notch Visitors Centers as well as at the Harvard Cabin (after Dec.1st) and caretaker cabin in Tuckerman Ravine.
  • Avalanche hazards can grow quickly now that we have some bed surfaces beginning to develop.  Be sure to check mountwashingtonavalanchecenter.org as winter continues to take hold up here.

I’m sure we’ll talk again soon.

Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

Print Version 11-28-2013 Informational Posting

Record cold air and snow on the way.

Is -15F and blowing over 100mph wintery enough for you?  Well I hope so because it’s cold enough for me.  Clearly winter is consuming our mountains with some more snow and additional white stuff arriving this week.  It’s definitely time to be prepared for full conditions in the hills and considering avalanche potential.  Although we are not in a General Advisory yet I have a feeling we will be soon.  Currently model runs for the expected mid-week surge of moisture are running warmer, with the rouge GFS starting to come into alignment with the rest of the pack.  This is expected to bring generally mixed precipitation to the region, leaning more heavily to rain than snow.  However the mountains could get a considerable shot of accumulation for the Holiday window.  We’ll keep an eye on it.  Regardless of how this plays out, 11” of snow over the past week is moving into all the nooks and crannies of the early season mountain.   The upslope snow anticipated over the next few days will move along the development of our initial bed surfaces.  How these bed surfaces progress in size will be the key factor in subsequent avalanche potential.

If you look for instability in a few places will you find it before the first official advisory? Yes.  Will it be a widespread problem found across the Ravines? No.  Don’t get caught by surprise and keep your eyes open for a pocket or two of instability.  The classic early season problems are usually found in Tuckerman’s Left Gully, Chute and numerous shelves and benches in the Center Headwall.  In Huntington, common locations have historically been found at the base of popular early season routes like Pinnacle and Odell.  Could instability be found in other locations? Of course, but these are where we see the majority of the early season developments.

  • As we progress towards the solstice daylight is waning.  A headlamp could become your best friend in the event of an injury or a longer than expected day.
  • Warm sun will undoubtedly make an appearance here and there loosening thin early season ice from the Ravine cliffs.  Be cautious when moving through or travelling below these locations.
  • Be sure to check current weather forecasts at the Mount Washington Observatory, posted at the Pinkham and Crawford Notch Visitors Centers as well as at the Harvard Cabin (after Dec.1st) and caretaker cabin in Tuckerman Ravine.
  • Avalanche hazards can grow quickly now that we have some bed surfaces beginning to develop.  Be sure to check mountwashingtonavalanchecenter.org as winter continues to take hold up here.

Chris