NASA-MODIS Rapid Response Record of 2011Hurricane/Tropical Storm Irene (Index)



This storm brought major flooding to large areas of the northeastern USA, from North Carolina and Virginia northward through New Jersey and into Connecticut, Massachusetts, Vermont, and New Hampshire.

Due to the large area included, the wide-swath coverage of the two MODIS sensors provides useful indication of which floodplains and shorelines were most affected. The maps provided here show, in red, the extent of flooding as imaged by the two MODIS sensors aboard NASA's Terra and Aqua satellites during the "accumulation period" indicated on the maps. We use only the highest spatial resolution (250 m pixels) bands, which provide the greatest detail, but also present diffficulties in distinguishing cloud and terrain shadows from water.

The MODIS data are processed to provide consistent water/land classification and boundaries. To remove moving cloud shadows, a two day accumulation period (two images each, from Terra and Aqua) is used to produce a single GIS file and map update. Still, many cloud shadows remain in this region in the map data, and must be manually removed. The maps only show areas where this labor-intensive step has been performed. The source GIS files cover much larger areas and this noise remains in these files.

NASA's MODIS sensors provide always-on coverage of the Earth's surface and have proved exceptionally valuable in immediate flood disaster assessment. Such remote sensing is often the first available after a major disaster and covers a very wide area twice daily. The follow-on sensor VIIRS, scheduled to be launched in the near future, will extend such capabilty. The maps do not replace, but are complementary to, mapping provided by other satellites at much higher spatial resolution and which show more detail.

These maps and the associated GIS data (.shp or Mapinfo file sets) are online publications of the Dartmouth Flood Observatory, G. R. Brakenridge, A. Kettner, F. Policelli, and D. Slayback, 2011. Please cite this source, and according to the Creative Commons licence terms provided in the DFO home page.

SE New York

Lower Connnecticut Valley

Western Vermont

New Jersey Shore