DFO Flood Event 4610 USA and Canada

Maximum Observed Flooding

Red is flooding mapped from Copernicus Sentinel 1 SAR data provided by the European Space Agency.

Blue is a reference normal water extent. Light gray is all previously mapped flooding.

For SAR-based mapping, a change detection method is used (GIS file names show comparison image dates). In some cases, "false positive" new water areas are included outside of the floodplains in these maps and files.

Geotif version

WMS version


Geotif version


Comparison of Image Data and Mapping Results

Red is flooding mapped from Copernicus Sentinel 1 SAR data provided by the European Space Agency. Blue is a reference normal water extent (SWBD. . Light gray is all previously mapped flooding. For this SAR-based mapping, a change detection method is used (GIS file names show comparison image dates). Top: Coeur d'alene River, false color composite using data from September 27, 2017 (before) and May 15, 2018 (during). The 10 m resolution of the SAR image has been somewhat degraded by application of a 5x5 low pass filter, to reduce speckle. A band ratio and flood image intensity algorithm is used to identify new water, already visble in the SAR image itself as red colors.


Event Numbers:

The Flood Observatory maintains a Global Active Archive of large flood events, 1985 to present. New major flood events are entered into this archive each week. A hand-drawn GIS polygon for each event outlines the estimated total area affected.

Event Maps and Copyright:

In some cases, severe or damaging floods become the focus of Observatory flood extent mapping. As part of collaborations with other organizations, including GEO and the Global Flood Partnership, the Observatory's maps and other data are made available here to the public. With attribution, they can be used for non-commercial purposes. With permission, they can be used for commercial purposes. Consult the Creative Commons license shown below and contact Robert.Brakenridge or Albert.Kettner (at Colorado.edu) if questions. Geotif versions and GIS files are also provided.

This event is selected for Observatory production of map and GIS data products.This web page and associated image and map (GIS) files are the permanent Flood Observatory record of this event. As the flood event proceeds, additional flood extent layers and maps may be added. The objective is mapping of the maximum extent flooded.

Description of this Event:

According to (for Canada/British Columbia) Flood List: "Thousands of people have evacuated their homes in British Columbia, Canada, after major flooding in the province that began on Thursday, 10 May 2018. British Columbia Premier John Horgan said, "The spring flood season is upon us. Heavy rainfall, warm weather and rapid snowmelt have triggered flood warnings and evacuations in the Interior. More than 4,000 British Columbians have been forced from their homes, while thousands more anxiously wait to see what rising flood waters will mean for their homes and their livelihoods." Evacuation orders affecting over 2,700 people were issued in parts of Kootenay Boundary, from Christina Lake through the West Boundary, including areas of Grand Forks. Firefighters rescued around 30 people by boat in Grand Forks, located at the confluence of the Granby River and Kettle River and one of the hardest hit areas.."

In addition to the maps above, for web map service-based (WMS) versions of the same mapping results, visit this DFO link. Zoom in to location of interest, and turn on appropriate event and other data layers.

Suggested citation:

Brakenridge, G.R. and Kettner, A. J., date, "DFO Flood Event #", Dartmouth Flood Observatory, University of Colorado, Boulder, Colorado, USA, http address.


Creative Commons License
The maps and web pages provided here are by G. R. Brakenridge and A. J. Kettner and allowable use is guided by the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Use for commercial purposes is by permission. Suggested attribution for this map: "Dartmouth Flood Observatory at the University of Colorado, from satellite data provided by NASA and Copernicus/European Space Agency".

Image Data Sources:

NASA Landsat 8 and Copernicus/ESA Sentinel SAR data if used in this map were obtained from the the U.S. Geological Survey Hazards Data Distribution System. and the Sentinels Science Data hub, respectively. Landsat 8 is jointly managed by NASA and the United States Geological Survey. Copernicus is supported by the European Commission..

MODIS data processing

Click here for access to an automated daily MODIS-derived .shp file GIS record (record commences in 2011). Choose appropriate 10 deg x 10 deg map sheet directory and appropriate dates; longitude and latitudes refer to upper left map sheet corner. Not all floods are mappable at the MODIS spatial resolution of 250 m. Some DFO event maps also include these automated MODIS data. If provided in the GIS file directories, the relevant MODIS "Current" file used is renamed to show the date used. These files are an accumulation of all MODIS water for that date and 13 days prior. The data shown on the maximum flood extent maps also refer to the MODIS date range; other satellite image dates are within that date range.

Obtain the GIS Data:

Flood extent files (Shp or Mapinfo) supporting this Flood Event Map are located here.

These files may include high spatial resolution mapping such as from Sentinel or Landsat, or lower resolution files from MODIS. File names commonly include the sensor source (e.g., S1 for Sentinel 1, LS8 for Landsat, MODIS for MODIS) and the image date.

Data from the Global Surface Water Explorer is included as part of the light gray previous mapped maximum surface water extent. It is based on Landsat images at a spatial resolution of 30 m (Jean-Francois Pekel, Andrew Cottam, Noel Gorelick, Alan S. Belward, High-resolution mapping of global surface water and its long-term changes. Nature 540, 418-422, 2016). The NASA Shuttle Water Boundary Data (SWBD) surface water extent (90 m resolution), blue, was derived from NASA's the 11-day February, 2000, SRTM mission and this "permanent" water layer was also corrected using Landsat data. These data are not provided in the GIS directories.

When used in the maps, NASA NRT Global Flood Mapping maximum water extent for the years 2013-2015, at 250 m spatial resolution, provide part of the (light gray) previous satellite-mapped water extent layer. DFO creates these annual water extent layers from data provided by that project, by accumulating into one annual file all of the daily .shp files for each year. DFO has also produced flood extent files through mapping of individual floods (~ yr 2000 to present); these are also included in this layer.

When used in the maps, Copernicus Emergency Management Service GIS data are imported and installed in the GIS data folder labeled "Copernicus". Delineation" files refer to flood inundation extents. Dissemination Policy: Under Copernicus and Commission Delegated Regulations, the information produced by the Copernicus Emergency Management Service shall be made available to the public on a full, open and free-of-charge basis. Attribution of the source is required "Copernicus Emergency Management Service, Directorate Space, Security and Migration, European Commission Joint Research Centre (EC JRC). Accessed date. http://emergency.copernicus.eu/".

Funding, Data, and Institutional Support:

The NASA Earth Sciences Program, the Latin American Development Bank, the World Bank, the European Commission's Global Disaster Alert and Coordination System, GDACS, and Copernicus Emergency Management Service, the Google Earth Engine research awards program, the Committee on Earth Observation Satellites (CEOS) Disasters Working Group-Flood Pilot, the Japanese Space Agency, and the European Space Agency all have supported the Observatory's work via research grants and contracts or by provision of free satellite-derived data.

The Dartmouth Flood Observatory was founded in 1993 at Dartmouth College, Hanover, NH USA and moved to the University of Colorado, INSTAAR, CSDMS in 2010. Its sustained operation depends on continued grant and project support. Gift contributions can be accepted; if your organization uses these data and maps, please consider helping to sustain this effort. The institutional support of both universities is gratefully acknowledged.

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