Avalanche danger update

A skier in Wolverine Cirque above Big Cottonwood Canyon triggered a soft-slab avalanche on April 7 at about 10,800 feet on a northeast-facing slope, and the Utah Avalanche Center logged the slide as skier-triggered, about 6 inches deep and 40 feet wide. (utahavalanchecenter.org) The skier wrote that the slab broke below his feet on his first turn after a ski cut, and he escaped by skiing left as the snow moved downhill. The Utah Avalanche Center rated it D1 and R1, which is the small end of the destructive scale but still big enough to knock a person off balance in steep terrain. (utahavalanchecenter.org) A soft slab is a cohesive sheet of snow sitting on a weaker layer, like a rug laid over marbles. When one part cracks, the whole piece can slide at once instead of just sluffing away grain by grain. (utahavalanchecenter.org) This one failed on facets, which are weak snow crystals that do not bond well and can linger under newer snow. The Utah Avalanche Center listed the problem as a persistent weak layer, meaning the bad layer can keep producing avalanches days after a storm instead of settling out overnight. (utahavalanchecenter.org) That is why spring can fool people. The Salt Lake forecast on April 9 said warming temperatures and overnight cloud cover were making wet avalanches possible by late morning, while recent snow was still unconsolidated on west-, north-, and east-facing slopes. (utahavalanchecenter.org) Wolverine Cirque had already shown warning signs earlier in the week. Separate Utah Avalanche Center observations from the same zone described cracking, collapsing, and another skier-triggered slide in lower Wolverine chutes as the aspect turned toward northeast terrain. (utahavalanchecenter.org 1) (utahavalanchecenter.org 2) The Utah Avalanche Center’s April 6 Salt Lake forecast put danger at Moderate on all mid- and upper-elevation slopes and warned that thin cloud cover can create a greenhouse effect that heats the snow surface faster than people expect. In avalanche terms, “Moderate” does not mean safe; it means human-triggered avalanches are possible. (utahavalanchecenter.org) The same spring pattern is showing up far from Utah. Norwegian outlets and SnowBrains identified one of the two people killed in the Hemsedal avalanche on April 6 as 29-year-old Guro Jordheim, a former University of Utah skier, and reported that four people were caught in that slide. (tv2.no) (snowbrains.com) The Utah incident and the Norway deaths are not the same kind of event, but they point to the same trap: late-season snow can look softer, warmer, and more forgiving while still hiding weak layers or turning dangerous as the day heats up. In both places, the terrain was steep enough that a small mistake or a small slide could turn into a very large consequence. (utahavalanchecenter.org 1) (utahavalanchecenter.org 2) (tv2.no) Spring avalanche travel usually gets safer only after the snowpack has gone through repeated melt-freeze cycles and locked up overnight. Until then, a northeast-facing bowl at 10,800 feet can still behave like midwinter for one turn and like spring slush by noon. (utahavalanchecenter.org 1) (utahavalanchecenter.org 2)