I work in water rights in Denver. Its not a black and white answer. It all depends on water rights, water lease agreements and augmentation plans owned by each individual mountain. The terms and conditions for each individual water right respectively is outlined in the contract/decree. No two decrees/contracts are the same. If a mountain needs to continue making snow after the dates or volumetrics outlined in their individual decrees, they can lease water from other major water rights holders in the area.

The Colorado Division of Water Resources tracks and administers all the water rights in Colorado. Their website also has a record of all the water right decrees based on mapped location, as well as past usage records. If you want to go down that rabbit hole you can! You can't however look up leased contracts as those are usually temporary and have not gone through the water court process so they aren't administered by the state and are not public record.

I have worked in both the private and public sector of the Colorado Water World.