Friday April 5, 2019
Loose Wet, Storm Slab
Travel & Terrain Advice
Best to avoid all avalanche terrain when the hazard is high. Stick to lower angled terrain and well treed zones. It might be the last chance of the season to shred the powder, but remember to play it SAFE.
Numerous loose wet avalanches up to size 1.5 were reported on Wednesday from Mt Washington avalanche control, as wet new snow fell on a old crust at treeline. No new reported since then.
During the day Friday at treeline (before the freezing level drops mid afternoon) and at lower elevations through the weekend, expect mixed precipitation to result in loose wet avalanche activity up to size two. These wet sloughs will be widespread on all aspects and will be touchy to human triggers at below treeline and lower treeline elevations.
Significant new snowfall and high to very high winds will certainly result in storm slab avalanches up to size three. These avalanches will be widespread on all aspects at treeline and in the alpine, especially NW to NE aspects where winds will transport and deposit even more snow. We can expect that these slabs will certainly trigger with with human activity and are very likely to fail with natural triggers (wind transport).
New snow falling on the spring crust from the past few weeks.
|Surface||new wet snow from Wednesday|
|Upper||crust from the past weeks of spring like conditions|
|Mid||a old weak layer sandwiched between well settled snow|
Some new wet snow (up high)and mixed precipitation (down low) fell Wednesday on to a thick crust that developed over the past weeks. Thursday temps dropped a bit and cooled the new snow.
A big storm with significant snow fall and high to very high winds over the weekend!
Friday - mixed rain and snow changing to snow as the freezing level drops, 15 to 50 mm of precip, temps 2 to -2, winds moderate to strong SE, freezing level 1500 dropping to 1000 m.
Saturday - 30 to 60 mm of precip (some mixed at lower elevations, all snow higher up), temps 0 to -2, winds strong to extreme from the SW to SE, freezing level 1000 to 1200 m.
Sunday - 6 to 22 mm of precip (some mixed at lower elevations, all snow higher up), temps 0 to -2, winds moderate SE to SW, freezing level 1200 to 1400 m.
Posted on Friday April 5, 2019 by Bill Phipps