Disclaimer

Last updated: October 28, 2026

Probabilities, not guarantees

SnowTally shows the chance that a given amount of new snow falls. A 30% chance means that, if the forecast is well calibrated, that much snow falls about three times out of ten in similar situations. It does not mean it will snow. Forecasts can be wrong, and the further ahead, the less certain they are.

Not for safety decisions

Do not use SnowTally for avalanche, backcountry, travel or other safety decisions. Check your local avalanche center, the National Weather Service, the resort and road authorities before you go.

NOAA data

Forecast inputs come from NOAA/NWS (National Blend of Models and WPC). SnowTally post-processes them; calibrated and adjusted values are SnowTally's own and are not official NOAA forecasts. SnowTally is not affiliated with or endorsed by NOAA or the National Weather Service.

SnowTally is not affiliated with or endorsed by any ski resort, OpenSnow or any other forecast service. Resort names are used only to identify locations.

Summit and base values

The main figure on each forecast page is for the elevation of a nearby reference weather station, where it can be checked. Upper- and lower-mountain values are elevation-adjusted estimates. They have not been verified at summit or base level, because no comparable snow measurements exist there.

Accuracy figures

Published accuracy comes from an after-the-fact test on archived NBM v4.x forecasts, November–April 2023-24 to 2025-26, scored on the held-out 2025-26 winter. It is not a live track record, and the current forecasts use NBM v5.0. See the methodology.

Questions: hello@snowtally.com