A mix of precipitation will affect the surface snow and travel conditions, but will not change the hazard rating. Ice building on slopes and surface objects will make conditions slick and treacherous for those entering avalanche terrain. Wet precipitation and warming temperatures later in the day will increase the probability of small avalanches in steep terrain on all aspects of middle and upper elevations.
Sleet, freezing rain, and wetting rain will contribute to today's wet loose avalanche problem. Frozen precipitation will change to rain throughout the day as temperatures at the highest elevations warm above freezing. Expect icy conditions throughout the day as ice accumulations grow and gradually melt as temperatures increase this evening.
A unique weather pattern has us with cold air temperatures around 15F near the summits with freezing rain actively falling. In most cases this would be snow however unsettled air, due to advection in the mid-level of our atmosphere, is creating this unfriendly mix of precipitation. Expect the low elevation zone to see the most accumulation of ice, with ½ inch possible. Sleet in the middle and upper elevations can be difficult to travel on or below as it may make an already slick situation more volatile.
Precipitation falling as rain will freeze upon contacting any surface colder than 0C degrees, adding weight and mass to those objects. Throughout the day as ice builds on objects and surfaces be conscious of the weight and mass it is adding to trees and structures. Ice accumulating on branches can snap trees or fall from above as chunks striking whatever is in its path. Water ice that previously clung to a slope may dislodge and fall in spectacular fashion to the ravines below.
It is difficult to say what will happen to the snowpack overall. Adding a significant amount of water and weight can make conditions hard to predict, and there is uncertainty in the outcome of today's weather. This is proving to be an excellent day to observe this unique weather phenomenon on Mount Washington.
Thanks to everyone who has taken the time to submit observations of snow and avalanche conditions, both inside and outside our avalanche forecast area. Please keep them coming.
The Lion Head Summer Trail is closed for the season due to avalanche risk. The Lion Head Winter Route is open.
