Flood - Red River (USA), April 1997
In April 1997, the regions of North Dakota (USA) and Manitoba (Canada) experienced some of the worst floods in their history, which caused severe damage to towns and farmland over a wide area. It was reported to be the largest flood the region had experienced in the 20th Century. The Red River Valley is subject to frequent flooding due to melting snow in the spring, but it is rarely so extensive. A major snowstorm in early April as well as double the normal amount of snow during the winter were the causes of the flooding as the snow melted. The flood reached its peak at the US-Canadian border on 26 Arpil, but continued to increase further north along the Red River Valley. A new lake formed in Canada (centred at Morris, near the town of Winnipeg, Manitoba) which reached a width of 50 km over 100 km in length.
  These images were obtained by mosaicking ten ERS-2 SAR images of four (two for each track) different acquisitions (one before the flooding and one during) along the Red River. The image is georeferenced to the north and shows the eastern part of North Dakota, part of western Minnesota (the Red River is the State boundary) and (at the top of the image) the southern part of Canada. The flooded areas appear in dark Blue and are located mainly below the river. The town of Fargo, badly hit by the waters, lies below the flooded area at the lower part of the image (clearly evident in the high resolution image). The town of Grand Forks is located at the bottom of the flooded area visible in the upper left corner of the right track image. Within both higher resolution images rectangular fields are clearly shown, with different brightness according to the different crops. The highways and major communication links appear as darker lines. Image area coverage: 250 x 500 Km
Images extracted from mosaic 1From Fargo to Winnipeg The first ERS-2 SAR mosaic covers an area of 200 x 100 km covering the upper part of the Red river, just before the Winnipeg Lake. In the upper left corner of the image is visible in blue the Manitoba lake; due to changed wind conditions the lake surface does not appear in black but appears in a bluish colour. The town of Winnipeg is clearly visible near the top right of the image along the Red river. Quite evident are the flooded areas south to the town along the river and how the artificial channel has protected the town from the flooding. A very large flooded area is located near the centre right of the image, where the Pembina river reaches the Red river.  
Images extracted from mosaic 2From Fargo to Grand Forks  
Two RADARSAT acquisitions are available, and examine the flooding in Morris (on 24 April 1997) and Winnipeg (on 01 May 1997).
|
||||||||||||||||||||||||||||||||||||||||||||||||||
