About

This site keeps the record of snowstorms in Minnesota, Wisconsin and Michigan’s Upper Peninsula. It states what was measured and where the number came from. The home page also shows what the forecast models say about the coming days: always the model run’s own numbers, named and timed, never a forecast of ours.

Sources

• Storm totals by station: NOAA NCEI Snowstorm Database, one file per major storm since 1900.
• Storm rankings: NOAA NCEI Regional Snowfall Index (Squires & Lawrimore), Upper Midwest region.
• Town histories: NOAA NCEI GHCN-Daily, the daily reports of co-op observers and airport stations. Volunteer CoCoRaHS gauges are left out of town histories because most began after 2008.
• Forecasts: the ECMWF ensemble (51 members) and NOAA’s GEFS (31), through Open-Meteo. Every run is recorded as it comes out, so a storm’s page can later show how the forecast changed.
• Photo: the site owner’s own.
• Ski venues: XC Index.
• Storm names: only where the Minnesota DNR State Climatology Office uses one.

Rules

• A storm at a town is a run of days with measurable snow (0.1 in or more), at most four days. A day with under half an inch between two snowier days separates two storms.
• A winter runs July 1 to June 30. It is ranked only when the station reported on at least 90% of the days from October 1 to April 30.
• Reports with a quality flag from NOAA are dropped.