Mountain snow at high elevations is changing as warming causes more melting and water to linger within it. We use satellite radar images from 2015 to 2024 to track when melting starts and when snow refreezes across the Wrangell and St. Elias Mountains on the border of Alaska and Yukon. We find that melting now reaches nearly all elevations, and water often remains trapped well into fall. Only the highest areas stay fully dry, showing widespread impacts of warming on mountain snowpacks.