Colorado’s jagged jumble of mountains, valleys, ridges and rivers creates a multitude of microclimates that can cause snowfall on a particular day to range from 2 feet of legendary Champagne Powder at Steamboat to just an inch at Aspen.
Joel Gratz and Sam Collentine, forecasters at OpenSnow, have a better handle on this than most people, and took some time away from predicting snowfall at Colorado ski resorts to offer clues about when it will snow the most at your favorite Colorado resort, starting with the basics.
Gratz said stormy weather involves a pretty simple recipe. In fact, he joked, the first page of all meteorology textbooks should say: “For interesting weather, you need moisture and rising air.”
Westerly winds high in the atmosphere pick up moisture over the Pacific Ocean. Some of that moisture becomes snow as the wind crosses mountain ranges west of Colorado, such as the Sierra Nevada in California and the Wasatch in Utah. Exactly how much is left for Colorado depends on a variety of factors. Rising air can be caused by a variety of factors, such as a low-pressure system, when the jet stream is directly overhead, or a storm system that is spinning strongly counterclockwise. It also rises when it hits a mountain range.
Wind direction is an especially potent factor in the Colorado snow forecast, and Gratz’s Daily Snows reports are peppered with comments about wind directions driving snowfall at different resorts.
“Sometimes the storm energy itself, the jet stream overhead, or other factors will just overwhelm a bad wind direction and generate the snow,” he said. “But in big mountains here in Colorado, in my brain, two-thirds of the time, the wind direction is a really, really big deal.”
Here are conditions that will generate the most snowfall at various resorts in Colorado:
When Colorado ski areas get their best snow:
Storms coming in from Southern California have no huge mountains to traverse before hitting Wolf Creek in Southwest Colorado. Loaded with moisture and rising sharply to Wolf Creek Pass, elevation 10,856 feet, these west-southwest and southwest winds make Wolf Creek, near Pagosa Springs, the snowiest resort in the state. “A southwest wind will crush Wolf Creek,” said Collentine, OpenSnow’s chief operating officer.
Steamboat, in northwestern Colorado, enjoys similar flat landscape to its immediate west, making for strong lift and good snowfall if the mountains in Utah have not stolen all the moisture.
When you get the right amount of moisture coming in on a west or west-northwest wind, and a temperature at the summit of about 5 degrees, you can get a “Steamboat surprise,” an unexpected, deep snowfall.
“At Steamboat, I have seen the biggest upside surprises,” said Gratz, CEO and co-founder of OpenSnow. “Not that they have the most surprises, but I’ve seen the biggest (surprises) out there.”
Crested Butte is surrounded by large mountains, the Elk Mountains to the northwest and to the southeast, in the direction of Monarch Pass. But a west-southwest wind “threads the needle” between high peaks, runs into Mount Crested Butte and snows big-time, Collentine said. “There’s a slight little sliver in the valley, and you’re running up to Crested Butte from the west-southwest. It’s wide-open.”
Vail does best in a northwest wind. “The air’s funneling right into the Vail Valley right along the Gore Mountains. At the ski resort, it’s rising. It just unloads on Vail,” Collentine said.
Winter Park also benefits from a north-northwest wind coming down the Fraser Valley.
Summit County resorts and Loveland, on the Continental Divide, have big mountains in almost all directions. They generally do best when the wind comes out of the north to northwest, but rarely get the really big snowfalls.
Snow can pile up at Breckenridge, Keystone, Arapahoe Basin and Loveland after a stormy low-pressure system has passed onto Colorado’s Eastern Plains and is strengthening there. The spinning storm draws moist air up from the Gulf of Mexico, wraps it across Wyoming’s high plains, then sends it south down into the Summit County mountains.
Copper Mountain is an in-between case. It can get snow like Vail on northwest winds. But, like its Summit County peers, its higher elevation can generate more snow than Vail or Beaver Creek.
Eldora, west of Boulder, can also benefit from the wraparound moisture brought in on an easterly wind from a storm tracking from southern Colorado or New Mexico onto the plains of Texas and Kansas. (This is the same wind that brings the smell of the stockyards and heavy snowfall to Denver.)
Telluride is tricky as the ski area is surrounded by big mountains on most sides. While strong storms can deliver decent snowfall with a wind from the southwest, the most snow at Telluride usually comes with a wind blowing from the west or west-northwest.
Purgatory, in the southern San Juan Mountains, gets the most snow if the wind is blowing from the south or south-southwest as it moves over the relatively lower-elevation terrain near Durango and hits the bigger mountains around the resort and Coal Bank Pass to the north.
Snowmass and Aspen Highlands can do OK with a wind from the west-southwest, but the biggest snowfalls on the four Roaring Fork Valley ski hills (including Buttermilk) usually are created by a wind from the west and west-northwest. Also, a wind from the northwest can generate significant snowfall at Aspen Highlands’ Highland Bowl and at Aspen Mountain.
