Castle and Andesite Peaks

We returned to Donner Summit today and found very different conditions from yesterday. The storm had deposited about 2 ft of new snow in this area. We started off by testing slopes nearby one that failed easily yesterday. Today, multiple ski kicks only elicited minor sluffs and small cracks in these slopes, whereas yesterday they would have avalanched.

As we continued up Castle Peak, we noticed that the strong sun had already formed some wet surface snow by 10:30 am. Ski kicks triggered 2-3 ft diameter pinwheels and small sluffs of wet snow on sunny slopes by 11 am. Cloud cover also began moving over the area around that time, but the damage had already been done. E-SE-S-SW aspects had shallow wet snow on them. Thin crusts also formed on some NE and E aspects due to brief sun exposure. 

We continued up the ridge past several wind-loaded test slopes that did not react to our ski cuts and kicks. We also saw 2 avalanches that must have occurred naturally yesterday. They had snow on them, and tests on wind-loaded features near those avalanches also did not produce signs of lingering instability. Eventually, we found colder, softer snow on shaded and sheltered N and NW aspects, but the sun had also started to change these slopes in the spots where it hit them.

On the way out, we returned to some east-facing slopes where ski cuts triggered more pinwheels and ski-width wide sluffs of wet snow.  

We dug a snowpit adjacent to one of the natural avalanches from yesterday. There was almost 3 ft of storm snow on top of the old snow surface in this wind-loaded area. The storm snow got progressively harder with depth and seems to be consolidating. Tests did not indicate lingering instability. The old snow below the storm snow remains wet.