From Tuesday's avalanche advisory:

Surface hoar and facets formed on almost all aspects and elevations of our advisory area (see multiple photos here). From Big Sky to West Yellowstone (and possibly Cooke City) it just got preserved under 1-2 inches of snow. Surface hoar is a persistent weak layer and as it gets loaded I expect to see avalanches. There’s a race in the northern areas to see if it’ll survive long enough to be buried; sun and warmer temperatures could destroy it today. Around Cooke City, besides an ocean of surface hoar, I found a rarer surface weakness formed from radiation recrystallization (video). Regardless of the type of facets formed, the avalanche danger could rise rapidly throughout southwest Montana with more snow.