Hydrological impacts of Hurricane Irene

August 29th, 2011 |
MODIS true color images: 16 August and 28 August 2011

MODIS true color images: 16 August and 28 August 2011

Heavy rainfall associated with Hurricane Irene included 20.40 inches at Virginia beach, Virginia and 20.00 inches at Jacksonville, North Carolina (HPC summary). Winds gusted as high as 115 mph at Cedar Island, North Carolina. The effects of the heavy rain and strong winds can be seen in a before/after comparison of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above). On the “before” image (16 August 2011), there was a large smoke plume seen from a fire that was burning in the Great Dismal Swamp area in far southeastern Virginia; on the “after” image (28 August 2011), water turbidity was significantly enhanced due to suspended sediment across the Outer Banks region of North Carolina — and a narrow filament of sediment was being actually being entrained into the flow of the Gulf Stream.

AWIPS images of the corresponding MODIS 0.65 µm visible channel data and the MODIS Sea Surface Temperature (SST) product (below) showed that the enhanced turbidity features seen on the MODIS true color image generally exhibited slightly cooler SST values (in the middle to upper 70s F, blue color enhancement) compares to the waters located closer to the Gulf Stream (SST values in the lower 80s F, darker red color enhancement).

MODIS 0.65 µm visible channel image + MODIS Sea Surface Temperature image

MODIS 0.65 µm visible channel image + MODIS Sea Surface Temperature image

Farther to the north, another before/after MODIS true color image comparison revealed additional areas of sediment being carried off the coast of the Northeast US (below). Also note that there was a great deal of sediment in the Hudson River (perhaps better seen in this 20 August / 29 August comparison).

MODIS true color images: 26 August and 29 August 2011

MODIS true color images: 26 August and 29 August 2011