Summary
NASA's Land, Atmosphere Near real-time Capability for Earth observation (LANCE) provides two global daily ~250 meter resolution NRT flood products:
- MCDWD from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the Terra and Aqua platforms
- VCDWD from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on the NOAA-20 (JPSS-1) and NOAA-21 (JPSS-2) platforms
Both products are currently at Release 1.1 (under MODIS collection 6.1 and VIIRS collection 2).
The LANCE MODIS product has been in production since early 2021. Prior to this, a legacy flood product (MWP) was generated from 2011 through 2022. The VIIRS product was released in April 2025. Apart from the difference in input data source (MODIS or VIIRS), the products are almost identical in algorithms and product formats. (See below for a summary of differences). With the Terra and Aqua satellites nearing end-of-life, the VIIRS product was developed to replace it.
For further details, please see the MODIS/VIIRS NRT Global Flood Products User Guide.
Additionally, a reprocessed historical archive of MODIS flood data (2003–2025) is available via NASA's Level-1 and Atmosphere Archive and Distribution System Distributed Active Archive Center (LAADS DAAC) for historical analysis and validation. See below for details.
Updates
April 6, 2026: A reprocessed historical archive of the MODIS flood product (MCDWD_L3) covering 2003-2025 was released, along with an ongoing archive of the NRT MODIS flood product, from January 2026 onward (MCDWD_L3_NRT). Both are available from LAADS DAAC. Please see the section below — MODIS Historical Reprocessed Archive Product Details — for more information.
Dec. 11, 2025: Both MODIS and VIIRS products were updated to Release 1.1 (User Guide revision F), with the addition of recurring flood classification. This tool helps discriminate unusual flooding from recurring flooding, which is defined as flooding that has been observed in the same location in roughly one third of the years in the reprocessed 22-year archive (2003-2024). (Please see the User Guide for details.) The VIIRS product was updated to use the final cross-calibrated surface reflectance for NOAA-21; this was an upstream update to the VJ209 surface reflectance product. The FLOOD viewer was also released to assist end users with evaluating this and other flood products.
April 16, 2025: VIIRS product Beta 1 was published (User Guide Revision E) and HDF product files were made available (including Geotiff files). The product was also added to Worldview. In this Beta 1 release, we used the preliminary calibration for NOAA-21 surface reflectance.
MODIS vs. VIIRS Flood Products
The MODIS and VIIRS products use the same overall algorithm and processing, with a few differences.
- Resolution: MODIS source imagery is nominally at ~250 m resolution for the primary red and near-infrared bands, while the VIIRS source imagery is 375 m resolution. To simplify adapting the code to work for VIIRS, the incoming VIIRS data is resampled to the same ~250 m latitude/longitude grid as the MODIS product.
- Observation times: Until 2022, the nominal equatorial overpass times for MODIS were 10:30 a.m. for Terra and 1:30 p.m. for Aqua. As the satellites reach end-of-life, fuel supplies have been exhausted, and overpass times had drifted to about 9:30 a.m. and 3:00 p.m., respectively, as of December 2025. They will continue to drift. All VIIRS instruments only provide afternoon observations, nominally ~1:30 p.m., although currently NOAA-20 and NOAA-21 are separated by about 50 minutes. The 50 minute separation was found to be sufficient to improve the product, compared to using data from only a single VIIRS instrument. But the VIIRS product is expected to be of somewhat lower quality than the MODIS product due to loss of the less cloudy morning observations provided by Terra.
- Current day files: The MODIS MCDWD product files are updated in-place as new observations are received and processed throughout the day. The user must check timestamps on the files to determine if they have been updated. For VIIRS, there is a separate hourly cumulative product generated for the current day: VCDWDG. The filenames have an additional element indicating the hour of production. For example: VCDWDG_L3_NRT.A2025063.2000.h08v06.002.h5 was generated at 20:00 (GMT). For a given tile, there will likely be two to four such files generated over the course of a day, as additional observations intersecting that tile are received. Thus, a user interested in the product for the current day should select the file with the highest hourly timestamp. It will incorporate all data received to that point in the day. The file generated with what would be a 2300 timestamp contains all the data received for the day, so is generated as the final VCDWD product, not as VCDWDG (and so will be located in the VCDWD download directories).
- HDF format: The MODIS product is generated in EOS-HDF4 (with .hdf file extensions), while the VIIRS product is in EOS-HDF5 (with .h5 extension).
MODIS NRT Product Details
| Short Name | MCDWD_L3_NRT |
|---|---|
| Long Name | MODIS/Aqua+Terra Flood Map Daily L3 Global 250m LL Grid NRT |
| Platforms | Aqua and Terra |
| Instrument | MODIS |
| DOI (Main HDF product) | 10.5067/MODIS/MCDWD_L3_NRT.061 |
| DOI (GeoTIFFs of each composite) | 1-day: 10.5067/MODIS/MCDWD_L3_F1_NRT.061 1-day with cloud-shadow screening: 10.5067/MODIS/MCDWD_L3_F1C_NRT.061 2-day: 10.5067/MODIS/MCDWD_L3_F2_NRT.061 3-day: 10.5067/MODIS/MCDWD_L3_F3_NRT.061 |
MODIS Historical Reprocessed Archive Product Details
In addition to the NRT MODIS flood product, a reprocessed historical archive (2003-2025) is available via LAADS.
Key differences: The NRT product (MCDWD_L3_NRT) uses expedited geolocation and atmospheric inputs to meet rapid delivery requirements, while the reprocessed archive (MCDWD_L3) uses standard science-quality inputs for improved long-term consistency. Both use the same underlying algorithm and provide the same flood map layers. See the product description document for additional details. Note that the historical product is only available as HDF files.
| Short Name | MCDWD_L3 |
|---|---|
| Long Name | MODIS/Aqua+Terra Flood Map Daily L3 Global 250m LL Grid |
| Platforms | Aqua and Terra |
| Instrument | MODIS |
| DOI (HDF product) | 10.5067/MODIS/MCDWD_L3.061 |
| Time period | 2003 to 2025 |
VIIRS NRT Product Details
| Short Name | Daily: VCDWD_L3_NRT Hourly: VCDWDG_L3_NRT |
|---|---|
| Long Name | Daily: VIIRS/JPSS1+JPSS2 Daily L3 Global Flood Composite 250m Linear Lat Lon Grid – NRT Hourly: VIIRS/JPSS1+JPSS2 Hourly Cumulative L3 Global Flood Composite 250m Linear Lat Lon Grid – NRT |
| Platforms | NOAA-20 (JPSS-1) and NOAA-21 (JPSS-2) |
| Instrument | VIIRS |
| DOI (Main HDF product) | Daily: 10.5067/VIIRS/VCDWD_L3_NRT.002 Hourly: 10.5067/VIIRS/VCDWDG_L3_NRT.002 |
| DOI (GeoTIFFs of each composite) | 1-day: 10.5067/VIIRS/VCDWD_L3_F1_NRT.002 1-day with cloud-shadow screening: 10.5067/VIIRS /VCDWD_L3_F1C_NRT.002 2-day: 10.5067/VIIRS/VCDWD_L3_F2_NRT.002 3-day: 10.5067/VIIRS/VCDWD_L3_F3_NRT.002 |
Support
- User Guide, Revision F, Dec. 11, 2025: MODIS/VIIRS NRT Global Flood User Guide
- Contact Earthdata Support
- To be notified of updates, please email floodmap-join@lists.nasa.gov (no text or subject required)
- To unsubscribe: e-mail floodmap-leave@lists.nasa.gov (no subject or text is required)
- Main POC - Dan Slayback, NASA Goddard Space Flight Center
Data Access/Download
View the flood data in Worldview, as well as the "Assessing Floodwaters" tour story.
The FLOOD Viewer web tool allows advanced users to easily compare MODIS and VIIRS flood products, including 1-day composites, with other flood products such as the NOAA-GMU VIIRS product and the NASA OPERA surface water products.
HDF and GeoTIFF Product Downloads:
Product downloads require free registration with the Earthdata Login registration system.
Automated and bulk download instructions.
NRT products are available from a primary server and a backup server:
MODIS HDF Files
For MODIS HDF files navigate to: NRT Data → allData → 61 → MCDWD_L3_NRT or navigate to:
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_NRT
VIIRS HDF Files
For VIIRS HDF files navigate to NRT Data → all Data → 5200 → VCDWD_L3_NRT (VCDWDG_L3_NRT for hourly) or navigate to:
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5200/VCDWD_L3_NRT
MODIS GeoTIFFs
For MODIS GeoTIFFs (one for each of the four flood composite products in each HDF file)
navigate to: NRT Data → allData → 61 → MCDWD_L3_F<X>_NRT (where X is the composite of interest: 1, 1C, 2, or 3) or navigate to:
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_F1C_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_F1_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_F2_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_F3_NRT
VIIRS GeoTIFFs
For VIIRS GeoTIFFs (one for each of the four flood composite products in each HDF file)
navigate to: NRT Data → allData → 5200 → VCDWD_L3_F<X>_NRT (where X is the composite of interest: 1, 1C, 2, or 3) or navigate to:
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5200/VCDWD_L3_F1C_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5200/VCDWD_L3_F1_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5200/VCDWD_L3_F2_NRT
https://nrt3.modaps.eosdis.nasa.gov/archive/allData/5200/VCDWD_L3_F3_NRT
MODIS Historical Archive
For access to the reprocessed historical archive (MCDWD_L3, 2003–2025), navigate to LAADS:
https://ladsweb.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3/
Additionally, the MODIS NRT product will be archived on LAADS from January 2026 onward. Note these are simply the original NRT files (MCDWD_L3_NRT) and have not been reprocessed as the above 2003-2025 archive has.
https://ladsweb.modaps.eosdis.nasa.gov/archive/allData/61/MCDWD_L3_NRT/
