This data set contains daily snow cover derived from radiance data acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-orbiting Partnership (NPP) satellite. The data is a gridded composite, generated from 6 minute swaths, and projected to a 375 m Sinusoidal grid. Snow cover is identified using the Normalized Difference Snow Index (NDSI) and a series of screens designed to alleviate errors and flag uncertain snow cover detections.

As of April 2025, this data set is retired and no longer available for download. Data from the "Golden Month," a 40-day window from 29 August, 2018 to 7 October, 2018 are available by special request from NSIDC User Services.

We recommend using <a href="https://nsidc.org/data/vnp10a1/versions/2">VIIRS/NPP Snow Cover Daily L3 Global 375m SIN Grid, Version 2</a> as an alternative.