Large avalanche in Hillman’s Highway

By Frank Carus

Date of Observation: February 14, 2019  4:00 PM
Location of Observation: Hillman’s Highway

Observed HIllman’s runout from the Tucks trail late in the day on Thursday the 14th but wasn’t safe to approach the runout until Friday the 15th. Some blocky debris in the dogleg appeared hard but a closer look on Friday revealed mostly softer debris with only a little bit of ice crust mixed in. Digging into the debris field showed that this avalanche was a fast moving and powdery with a significant powder cloud/air blast that broke tree branches 10′ up and up to 2″ in diameter. Two ~10″ trees at the edge of the debris field were broken off leaving short stumps and another was pushed over. The debris was smooth and flat and snow was plastered onto the uphill side of remaining forest indicating that the debris reach a turbulent and fast moving flow with a significant powder cloud. and had run the full ~1300′ of the gully. No crownline was visible in the fog or accessible. The adjacent Lower Snowfield crownline leads me to believe that the avalanche released at the density change mid-storm and quickly entrained the first couple of inches of drier, lighter snow from the beginning of the storm. SS-N-D3-R4-S


ABOUT THESE OBSERVATIONS

Snowpack observations are one part of the complex puzzle which is your decision to enter avalanche terrain. Some observations may include stability tests. It’s important to understand that the results of a stability tests are seldom conclusive anywhere, but particularly in snow climates and terrain like ours where the primary driver of instabilities is wind drifted snow. Many stability tests exist and each works best with specific avalanche problem types. Stability test results should never be used alone as an indication that a slope or conditions are safe particularly when more obvious red flags are present. Please use this page as part of your information gathering process, but don’t make decisions based on a single piece of information. A good article that summarizes some of the issues associated with snow and avalanche observations can be found here.

The Mount Washington Avalanche Center cannot verify the quality or accuracy of any observations that come from the general public.

SUBMIT YOUR OBSERVATIONS

See an avalanche or evidence of previous avalanche activity?  Near-miss? Snowpack observations?

Your observations are valuable to an accurate forecast! We welcome observations from everyone. You don’t need to be an avalanche professional to submit helpful observations, just be as detailed and accurate as you can.