Detailed Observation
Date | 2020-12-18 |
Location | Haines |
Observer | Jeff Moskowitz |
Avalanche | N |
General Observations
Lutak Zone: Avalanche hazard increased through the day as the south wind picked up in the afternoon blowing snow around building storm slabs. Red flag conditions included a localized whumph 1-2′ down below the weakening supportable crust and small shooting cracks within the 14″ of new storm snow. Not stoked about all the melt-freeze layers and poor structure beneath the surface. Be careful out there, while it may be tempting to seek steeper terrain as the snow becomes heavier, be aware of the hazards and rapidly changing conditions. Scroll down to read more…
Uploaded Images
Weather Observations
New Snow Amount | 14 |
Foot Penetration | 21 |
Ski Penetration | 18 |
Wind Speed | Calm from the North; then Moderate gusting strong from the South |
Wind Direction | North, then from the South |
Sky Cover | Obscured |
Snowfall Rate | S1-S3 |
Rain Rate | Nill |
Temperature | 19-20F |
Snowpack Observations
On a north aspect at 2000' extended column test results were not good - ECTN 5 & 6 down 14" - suggest easy results within the new storm snow over the upper most melt-freeze crust (that is breaking down and having more stress added by new snow and increasing temperatures). Propagating test results ECTP 16 & 17 down 27" failed below a melt-freeze crust on a soft airy pocket over a knife hard melt-freeze crust (see photos where there is a gap).
Test result illustrates the potential of a slab avalanche that would have a lot of energy and destructive potential, if it were triggered. The structure has several melt-freeze/facet combos with notable moist rounded melt-forms that appear to be faceting ~4' down and are trapped below a 10" crust. The crusts are acting as a vapor barrier and this coupled with a strong temperature gradients helps accelerate weak snow grains above and below these melt-freeze crusts.