How Snowcall works

Where the numbers come from

Every resort has a federal snow station nearby, part of the SNOTEL network run by the USDA. Each one measures how deep the snow is and how much water is in it, every day, the same way at every mountain. We use those stations instead of resort snow reports, so every mountain is measured by the same ruler. The sky and wind come from the National Weather Service forecast.

How we decide

Each morning we look at two things: did real snow fall in the last two days, and will the sky be clear? Fresh snow means the station's snow got at least 4 inches deeper, or 3 inches when it stayed below freezing, or it caught a heavy, cold snowfall that packed down overnight. Clear means the forecast shows less than 30% cloud between 9 and 4, while the lifts run.

• Bluebird: fresh snow and a clear sky. The rare one.
• Powder: fresh snow, cloudy sky.
• Storm: snowing today.
• Bluebird Groomer: no new storm, sunny sky.
• Quiet: no new storm, gray sky. Usually short lines.

"Dense" snow

Sometimes heavy snow settles overnight and the depth barely changes, even though a real storm came through. The station also weighs the snow, so we can still catch it. Those days are marked "dense".

Tomorrow

Tomorrow is a forecast, so it's shown as Likely or Possible, never a percentage. After 5 PM, Snowcall opens on tomorrow.

How often is there fresh snow?

We checked twenty winters of station readings, 2006-07 to 2025-26, counting only days the lifts were running.

Southern Idaho: Brundage averages about 34 fresh-snow days a season, Sun Valley about 31, Bogus Basin about 28 and Tamarack about 24. The best week across the region has been Dec 22–31. See all 20 winters.

Northern Utah: Snowbird averages about 46 fresh-snow days a season, Alta about 43, Brighton about 36, Solitude about 35, Beaver Mountain and Snowbasin about 32, Powder Mountain about 29, Park City Mountain about 28, Deer Valley about 26 and Sundance about 24. The best week across the region has been Feb 15–21. See all 20 winters.

Lake Tahoe: Northstar, Palisades Tahoe and Mt. Rose average about 34 fresh-snow days a season, Sugar Bowl about 30, Heavenly and Kirkwood about 29, Sierra-at-Tahoe about 28 and Diamond Peak about 22. The best week across the region has been Dec 22–31. See all 20 winters.

Lift days come from resort announcements and news. For a few winters, mostly before 2016, no opening or closing day could be found, so those use that mountain's 2016-26 average.

How often is it bluebird?

Rarely, and that's the point. Most fresh snow arrives with the storm still overhead. Counting only lift days:

Southern Idaho: Bogus Basin and Sun Valley average about 4 bluebird days a season, Brundage about 2 and Tamarack about 1. Some winters have none.

Northern Utah: Snowbird averages about 7 bluebird days a season, Solitude, Brighton and Alta about 6, Snowbasin, Park City Mountain and Deer Valley about 4 and Beaver Mountain, Powder Mountain and Sundance about 3. Some winters have none.

Lake Tahoe: Northstar, Palisades Tahoe, Mt. Rose, Heavenly and Sierra-at-Tahoe average about 5 bluebird days a season, Sugar Bowl and Kirkwood about 4 and Diamond Peak about 3. Some winters have none.

Sky history: contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

What we can't see

A station measures snow in one spot. It can't see wind-scoured ridges, crust, or which runs were groomed. Tamarack's numbers come from a station about 10 miles away, and Sun Valley's from a station higher than the base. In Northern Utah, four stations each serve two mountains (so neighbours like Snowbird and Alta often share a call), Powder Mountain and Snowbasin share one about 9 and 12 miles away, and Sundance's sits higher than the resort. At Lake Tahoe, Northstar's station is about 15 miles away and higher than most of its slopes (its snow can read high), Diamond Peak's is about 6 miles away, and Sugar Bowl's sits at base height, where a warm storm can fall as rain. Lake Tahoe's sky window, 9 to 4, is Pacific Time. Always check the resort's own report before a long drive.

Sponsors

Snowcall is free, and local businesses help keep it that way. A sponsor gets one small, labelled spot on a page, below the calls. Sponsors never affect calls, alerts or the numbers: those come only from the snow stations and the forecast, worked out the same way for every mountain, whoever sponsors it.

We tell sponsors how many times their spot was shown and tapped, as daily totals by page, device type and rough city. Nothing about you. Privacy

Some spots may show an affiliate link instead: a product or place to stay that pays Snowcall a small commission if you buy through it. It's labelled "Affiliate link", and it never affects calls either. When a spot has neither, it shows our own "This spot is open" note.

Run a local business? How sponsoring works.

Rule version 3.3

If we change how we decide, the version number changes here.

Snow data: USDA Natural Resources Conservation Service, SNOTEL. Forecasts: National Weather Service. Snowcall's calls are our own reading of that data, not official USDA or NWS information. Ski area names are trademarks of their respective owners. Snowcall is not affiliated with, endorsed by or sponsored by them.