Uphill-Colorado-Ski When the lift stop and the sun begins to fall, many Coloradans strap on the skins and head uphill for some solitude. (Crested Butte Mountain Resort))

Whether it be Covid-distance crowds, the high price of lift tickets, or simply a need to breathe the Great Outdoors, the participation in uphill skiing has exploded in Colorado this season.

In response, Colorado resorts typically dictate where and when you can climb, and put signs on trails open for downhill runs. All resorts have an uphill hotline or website page with what's open for uphill travel on any particular day. And all warn after-dark uphillers to be on the lookout for snowcats, snowmobiles, and maintenance personnel who work the slopes at night. Most dedicate a few uphill routes, and several cap how high you can climb, like Telluride at top of Lift 10.

Of Colorado's 20 ski and snowboard resorts, about half of them require an uphill pass/armband separate from a day or season pass. Echo Mountain, Purgatory and Silverton Mountain do not permit uphill traffic at any time.

Recently resorts have begun charging for the uphill privilege. Usually, season pass holders can go up for free, but some charge an add-on cost. Here's a look at those that require a payment:

For newcomers, all four mountains in the Aspen-Snowmass complex offer a two-day uphill clinic.