Vail & Summit County

Cool and windy to start with, quickly warming temperatures. Mostly clear skies. Local SNOTEL stations were 5 to 10 degrees off of their daily record temperatures. Based on the NWS forecast, mountain towns and urban areas will exceed record temperatures, setting all-time March records, while SNOTEL sites generally above 10,500 ft (most of the elevations covered in the avalanche forecast in Summit County) will be cooler than record highs. Still very hot!

Above treeline has been hammered by recent winds. Surfaces are mostly hard drifted slabs of snow and sastrugi. Hard surfaces in the morning began to soften by afternoon. On an east-facing slope at 12,300 ft we found a homogenous, dry, one-finger hard slab sitting over fist-hard basal facets. The snowpack was about 1 meter deep. This structure would be most worrisome for larger wet avalanches. There is significant uncertainty about whether, even with multiple days of very warm temperatures, water can penetrate this dense slab and soak the basal facets. Starting Friday, I would travel like this is going to happen, and gather evidence it is safer rather than vice versa. East-facing slopes still are worrisome for dry Persistent Slabs and with the structure we found, we still can't rule out triggering a dangerous, wide, dry persistent slab avalanche. Southeast-facing slopes also had a mostly dry snowpack. This changes quickly near treeline, and at this elevation, the snowpack is composed of multiple, hard, buried melt-freeze crusts with signs of previous meltwater that had moved to the ground. Although meltwater has moved through the entirety of this pack, basal facets remain dry, so we can't rule out this elevation/aspect for wet slab avalanches either. We also dug on a south-facing slope at 12,000 feet and were surprised to find dry basal facets beneath a mostly consolidated, spring-like snowpack. We will need more information from this aspect/elevation to determine if basal facets are dry on other high elevation south-facing slopes as this doesn't line up with other observations. On a west-facing near treeline slope, the snowpack was about 45 to 60 cm deep where we could find snow. The snowpack was mostly dry with very weak basal facets near the ground. These west-facing slopes may not produce wet slabs, unless they were previously cross loaded and have a slab, but they most certainly could produce gouging wet avalanches. As for loose, wet avalanches, we didn't see any evidence of them today. With the hard surfaces and lack of soft, cold snow, there wasn't much that the sun could do to change dense, hard snow into cohesionless wet avalanches.