Flood of American Midwest of 1993

The flood of American Midwest of 1993 occurred between April and October 1993 in the basin of the river the Mississippi and its affluents, from of which the river Missouri, following constant rains beginning the preceding autumn. The flood of the area of the Midwest is one of the more devastators and most expensive of the history of the the United States, causing for more than 15 billion $US (1993) damage and death 50 people. It has affected a good part of the States of the North Dakota, South Dakota, Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska and Wisconsin, a 1200 km length zone on 700 km broad. The surface flooded on this territory was of 80000 km ². It is the most important flood since that of 1927 in terms of duration, of flooded surface, people moved, damage with harvests and the property, as well as going beyond of the level of water. The flood of 1993 even exceeded that of 1927 in certain fields.

Causes

zoomé --> In 1991, the long eruption of the volcano Pinatubo dispersed in the atmosphere of great quantities of dust which was spread around the sphere. These last being able to be used as cores of condensation for the production of Precipitation S, it was suggested that this unusual contribution increased the quantities of rains lasting the year 1992, in particular during the autumn in Midwest. Moreover, the winter 1992-93 on this area was particularly snow-covered. The grounds were then saturated with water and the tanks reached their maximum level in the basin of the Mississippi river and Missouri.

During spring 1993, atmospheric circulation followed a very stable and repetitive diagram bringing depressions charged with rains on the threatened zone. This contrasted with the dry time which gave conditions of dryness in the south-east of the United States. Between on April 1st and the August 31st, the part of center-is of Iowa received up to 1250 [[millimetre]] S and the center-north of the Grandes American Plains, from 400 to 750% of normal precipitations.

Chronology

April, May and June

In April, the Mississippi reaches a dimension from 2 to 3 meters superior on the level of flood then a light fall starts. In May, the river is again in prey with a similar rising then at the beginning of June, a new fall brings back it under the dimension of alarm. Serious floods are due to the Redwood river with the Minnesota as of May. The 22 of this same month, Sioux Falls (South Dakota) only receive 192 mm of rain in three hours. During the period from May to July, 575 mm fall there what makes of it the three months period most rainy of the history of this city.

It falls 25 mm (Kansas City (Missouri)) to 100 mm (Springfield (Missouri)) moreover than the normal in June and water of the Mississippi approaches the critical point again as from the second week on most of its course. The river Black with the Wisconsin as well as the rivers Missouri and Kansas start to overflow locally, a historical level over one 228 years period. The wall of reserve of believed around the city, high 16 m and built to contain a rising identical to that of the flood of 1844, manages to avoid the overflow of accuracy. Water arrived to only 0.6 m of its top. The peak of the wave then moves towards the confluence of the river Ohio to Cairo (Illinois). Only minor overflows are further announced because Ohio, located at the east of the United States, did not undergo strong precipitations and is even in a state of dryness. If Ohio had brought large quantities of water, the flood would then probably have been more devastator than that of 1927 on the low Mississippi.

August

, The Mississippi pours 30600 m ³ /s, what to fill each second more than 10 Olympic Piscines

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