General Avalanche Advisory, Thursday 12-05-2013

Expires at Midnight Saturday 12-07-2013

This is the initial GENERAL AVALANCHE ADVISORY for the 2013-2014 season.  A new General Advisory will be issued if conditions warrant or within 72 hours of this release.   

A General Advisory is issued when there are limited instabilities within the entire forecast area. However, there are snowfields that are growing in size and may harbor some instabilities. Some examples in Tuckerman include Left Gully and the Chute. These are two areas that grow in size the earliest and present the largest potential bed surfaces for future snow to load on. Yet, the smaller snowfields between ice bulges across the Tuckerman Headwall can be more problematic because of the concentration of climbers on this early season ice.  Be wary climbing under other parties.  In Huntington, typical problems for the early season climber are often in the snowfields below the first pitch of ice on various routes.  Examples include underneath Central, Pinnacle and Odell.  Keep this in mind and don’t underestimate these smaller patches of snow on your chosen ice climbing route.  If a snowfield is big enough to recreate on, it’s big enough to avalanche.

Since the warm up and big rain on Wednesday 11/27 we have received snow every day except for one 24 hour period.  This has brought the mountain about 8” (20cm) of snow over the past week which has helped grow several of the mountain’s east facing snowfields.  Today, Thursday 12/5, mixed precipitation is forecasted to change to freezing rain (ZR) and then all rain through the higher summits.  This may cause a stability problem or two depending on how much rain we actually receive after the glazing crust from ZR.  The bigger issue into the weekend will be new areas of slab that will form on the new surface ice crust.  As this system moves out of the region cold air will change precipitation back to snow for early Friday morning and through the day.  Winds are expected to be from the W at 55-75+mph (90-120+kph) during this snow shower period.  Expect to find areas of new slab sitting on the old icy surface on a variety of snowfields in both ravines.

The weekend is expected to be pretty nice likely offering good visibility.  It’s probable that the climber who spends time analyzing a route from below will be able to see where new and old snow is located.  This should allow planning a route sticking to stable snow.  If visibility does not make this possible expect pockets of new snow to be poorly bonded to the old surface if you encounter them while on route.  We’ll watch the snow coming for Monday and discuss that in the next advisory.  Check www.mountwashingtonavalanchecenter.org frequently as we move through December for the latest avalanche advisory before heading into avalanche terrain. We’re excited to be back at it and look forward to seeing you in the mountains!

Please Remember:

  • 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 the caretakers at Hermit Lake Shelters or the Harvard Cabin. Posted 0745. 12-05-2013. A new advisory will be issued when conditions warrant.

 

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

12-05-2013 Print Version