About SnowDex

SnowDex answers two questions for any ZIP code in the contiguous United States: how much snow fell, and how much is coming. It is built and run by an independent developer, not a weather company. An iPhone app is in the works.

What it uses

Snow that fell comes from NOAA’s National Snowfall Analysis, published by the National Operational Hydrologic Remote Sensing Center (NOHRSC) on a ~4 km grid. Snow that is coming comes from the National Weather Service gridpoint forecast. Where this website cites 30-year averages it uses the NOAA NCEI 1991–2020 U.S. Climate Normals. All of it is public U.S. government data. NOAA publishes it; NOAA does not endorse this site.

What it deliberately does not claim

• No measurement at your door. Every total is labelled an estimate for a ~4 km grid cell, with the exact time window it covers.
• No accuracy percentage. The estimate is usually close in ordinary storms and can be far off inside narrow lake-effect bands; one percentage would hide that. Pages in lake-effect belts say so next to the numbers.
• No “final” numbers. NOAA keeps refining each analysis for about five days; a total says when it may still change.
• Not a warning service. Official winter-storm warnings come from the National Weather Service.

Contact

Corrections, questions and feature requests: support@snowdex.app. If a number here looks wrong, say so — that is the single most useful message this project can receive.