North American Snowmelt Timing Maps from MODIS 2001-2018

Snowmelt timing maps for North America provide the day-of-year of snow disappearance per 500-meter pixel from 2001 to 2018. The dataset is derived from MODIS MOD10A2 Collection 6 8-day snow cover composites and includes cloud interference maps and a count of valid observations per pixel. It is produced by the National Aeronautics and Space Administration and represents a consistent 18-year record.

Use Cases

• Analyzing interannual variability in snowmelt day-of-year (DOY) across North American watersheds.
• Masking cloud-obscured pixels using the provided cloud interference maps for cleaner analysis.
• Assessing data reliability by using the count map showing the number of years with a valid snowmelt timing value per pixel.
• Investigating long-term trends in spring snow cover duration from the 2001-2018 time series.
• Validating snowmelt timing in hydrological or climate models using the MODIS-derived per-pixel observations.

Strengths

• Provides an 18-year continuous record (2001-2018) for trend analysis.
• Offers a specific per-pixel snowmelt detection algorithm based on consecutive snow-present readings.
• Includes ancillary data layers for quality assessment, such as cloud interference and observation count maps.
• Cross-platform presence on Data.gov and NASA Earthdata indicates recognized importance and reliability.

Limitations

• Spatial resolution is limited to 500 meters, which may not capture fine-scale topographic effects on snowmelt.
• The algorithm requires two consecutive snow-present readings before a snow-free reading, potentially missing early or intermittent melt events.
• Sources conflict on the last updated date: Data.gov lists 2026-03-12 (likely a metadata error), while NASA Earthdata lists 2018-12 31 (end of data coverage).

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Time-series analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) MOD10A2 Collection 6 8-day composite snow-cover products.

Time Range

2001-01-01 to 2018-12-31

Freshness

2018-12-31 23:59:59.999000

Geography

North America