This is an early season GENERAL ADVISORY. Use of the 5 scale avalanche danger rating system will begin when conditions warrant. Until then new advisories will be issued as needed. REALIZE AVALANCHES MAY OCCUR EVEN THOUGH WE ARE ONLY ISSUING A 'GENERAL ADVISORY' DUE TO ISOLATED INSTABILITIES. Remember if the snowfield is large enough to ski or recreate on it's large enough to avalanche. Check "tuckerman.org" frequently as we move into November and certainly check for the latest avalanche advisory before heading into avalanche terrain.

On Wednesday night (November 12th) we received heavy rain on Mount Washington with some thunder early the following morning with temperatures around 3 degrees C (38 F). At that point there was NO snow in the Ravines, but a significant amount of ice survived the rain in Tuckerman. As the front came through mid Thursday morning temperatures plumetted forcing rain over to sleet and icing followed by snow. By midday we were picking up about 1.5 cm (.6 inches) of graupel an hour. Each crystal varied in size from 1.5mm to 4mm in diameter. I suspect due to strong winds graupel rolled and pooled into scattered pockets in the Ravines. Particularly, on "shelves" in the Tuckerman Bowl and Headwall. Approximately 5cm (2 inches) of graupel was covered by an additional 15.5 cm (6 inches) of snow through the night. By Friday morning a total of 20.5 cm (8 inches) of snow was observed at the snow stake with 3.45 cm (1.35 inches) of water equivilant, for an average density of 16.8%. High winds from the W and NW are moving substantial amounts of this new snow into lee areas in both ravines. As of 2:00pm Friday afternoon summit winds were blowing 193 kph (120 mph) with a temperature of -18 C (0 F).

As of Friday afternoon we have rapidly moved from late Fall, with no snow, to full Winter conditions within a day and a half. New snow is being blown into lee areas on top of a base of graupel on scattered blue ice. The temperature drop has generated a gradient within the new snow pack condusive to facet growth, potentially near the grapel layer. It will be something to watch. So, unstable slabs may be found, but due to starting from no snow as of 2 days ago they are very isolated. However, someone ignoring all instability clues may find one of these areas. The most likely locale would be on a pocket of water ice in Tuckerman.

Be aware that a small slab or sluff can be very dangerous. This is particularly true in the steep gullies and slopes of Tuckerman and Huntington Ravines for early season ice climbers. As a climber picks their way through a route they will usually cross small pockets of snow. Often this snow was deposited over blue ice, making for a poor bond at the interface. Consider this ahead of time and place protection before crossing suspect slopes. Approach early season snowfields with skepticism and be conservative while on them, near them, or in their runout zones. It doesn't take much snow to knock you off your feet and depending how high you are this could be a significant problem.

We are absolutely in early winter in the high mountains so don't plan on being able to follow summer trails safely. Trails going through Ravines and Gulfs are buried with snow in most areas and require winter gear, i.e. winter clothes, ice axe, crampons, avalanche beacons, shovels, and probes.

Review your safe travel rules, techniques for assessing snow stability, and sign up for an avalanche course. We have all the avalanche courses offered in the valley this winter on our website, tuckerman.org.

AS ALWAYS, THIS BULLETIN IS ONE MORE TOOL TO HELP YOU MAKE YOUR OWN DECISIONS IN AVALANCHE TERRAIN. It should be used along with your own snow stability assessments, knowledge of safe travel techniques, skill in reading mountain weather's effect on the snowpack, and avalanche rescue.

United States Avalanche Danger Descriptions. ù