2002 Annual

Thursday, 17 January 2002: 1:30 PM
A comparison of recent large-scale floods in the north-central U.S.: climatology, impacts, mitigation, and the value of improved predictions
Michael A. Palecki, ISWS, Champaign, IL
The flooding in the north-central U.S. during Spring 2001 along the Upper Mississippi River and Red River of the North were similar in magnitude in a number of locations to the record floods of 1993 and 1997 in these basins. The climatic mechanisms bringing about the 2001 floods were most similar to the 1997 flood season, but some of the resulting persistent precipitation anomalies were reminiscent of 1993, allowing a basis for comparison from a prediction / mitigation / impact perspective. The climatology of the three large-scale floods will be placed in the context of the record of climatic change and variation during the 20th Century; the period since 1989 has been especially wet in this region. Following this, the tremendous negative impacts of the 1993 and 1997 flood events will be contrast with the much smaller societal impacts of the 2001 event. In 2001, most locations recording similar river stages to those that caused devastation in 1993 and 1997 responded promptly to early warnings and successfully mitigated the potentially devastating 2001 floods. The earlier extreme events helped to build-up institutional memories that aided in mitigation, and also provided incentives for improvements in hydrological prediction and flood protection in urban centers that occurred during the intervening period. This study concludes that the resiliency of the populations living in flood hazard zones along the Upper Mississippi and the Red River of the North has increased through experience. Secondly, improved long-lead flood-level predictions also helped to develop appropriate and timely responses to the 2001 floods. Finally, the judicious application of climate information, impact analyses, and improved prediction systems can be used to enhance resiliency in places before a calamitous event forces society to learn the hard way about hazards inherent in future climate variation and change.

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