Hatcher Pass received about 3″ of new snow 4/3 with .3″ SWE.
A large avalanche cycle occurred early in the week after strong winds on 3/29- 3/30. Strong winds starting early Sunday morning at 1am. ENE/ESE 16-23 G 34-51 for about 15 hours at 4500′ on Marmot.
The largest avalanches were observed in the Arkose ridge area due to stronger Matanuska winds. Natural and human triggered avalanches occurred near Stairstep, Punk Spines, Gold Mint, and the Willow side of HP.
Avalanche outlook for the week :
In most locations at Hatcher Pass, snow depth remains deep ranging from 3 to 6 feet. HP could receive a few inches of new snow in the next couple days accompanied by light winds and cooler temps towards Monday.
A variety of conditions exist including a few inches of new snow from 4/3, buried crusts, sastrugi, and old wind slabs. Temperatures are expected to stay below freezing at night at 4000′ through the week, so we are not worried about a wet slab problem yet. If new snow amounts or wind increase in the next several days, storm slabs and/or wind slabs could be a problem. We continue to be most concerned about the deep persistent slab problem, wet avalanches in the coming weeks, and cornice fall.
Deep persistent slab
This problem continues to linger and although less of a problem now, expect that to change with the next wind event, loading event, or sudden increase in temperature. Since January, we have seen intermittent remotely and human triggered avalanches, mostly by large loads such as snow machines, failing on this early January facets weak layer. This problem is a result of poor structure and exists on all aspects, and all elevations. Most common locations to trigger this problem will continue to be East to South to West below 3800′. Persistent slabs may be 1-4 feet deep.
Cool temperatures have kept wet avalanches to a minimum. Expect more wet-loose activity once temperatures consistently rise above freezing. If crusts soften, become punchy and saturated, wet loose sluffs will be easy to trigger, most likely on SE to SW aspects at all elevations, although more likely at low and mid elevations. Rollerballs are also a sign of warming and time to move to cooler terrain.
Cornices are unpredictable, large, and continue to hover over many leeward aspects making route choice challenging and dangerous. Please continue to give cornices a wide berth and reduce exposure below them. It will be possible for cornice fall to trigger the deep persistent slab problem.