Contact:  Barry Reichenbaugh            FOR IMMEDIATE RELEASE
          NWS Grand Forks Office        July 25, 1997
          Stephanie Kenitzer
          

A team of experts today released preliminary findings from their study of National Weather Service forecasts and services during the April 1997 floods in North Dakota and Minnesota on the Red River of the North.

An interagency disaster survey team led by the National Oceanic and Atmospheric Administration found that complex river characteristics and limitations in current NWS flood forecast methods were the primary cause of changes in forecasts of the flood crest at Grand Forks, N.D., and East Grand Forks, Minn., as the record-setting crest approached the two cities.

"The same forecast techniques that produced very good predictions of flood stages on other portions of the Red River were not as effective for the Grand Forks/East Grand Forks area of the river," said Edward Johnson, co-leader of the NOAA survey and chief of the Hydrologic Operations Division, Office of Hydrology, NWS. "Our models did not fully account for the submerged bridges and the very flat terrain downstream that backed up water in the town."

The survey team also suggests that the NWS needs to improve the methods used to estimate and convey the uncertain nature of its flood forecasts and outlooks to officials and the public.

"Our discussions with NWS customers in the Red River valley indicated that there needs to be greater understanding of the meaning of long-range flood outlooks and short-range flood forecasts. We have to ensure that people clearly understand that river levels could be higher or lower than called for in the outlook and that our confidence grows as we issue forecasts and get closer to the event," Johnson said.

In briefings for members of Congress and for local and state officials of Minnesota and North Dakota, the survey team also noted that "the most promising method" for improving hydrologic forecasting is the Advanced Hydrologic Prediction System demonstrated on the Des Moines River Basin this past spring. The system combines long-range weather and climate forecasts with hydrologic models to produce long-range flood probabilities and probability-based flood inundation maps.

Flooding on the Red River of the North established twentieth-century records at most locations along the river and was particularly devastating in the towns of Grand Forks and East Grand Forks. With the exception of Grand Forks, which exceeded the previous record, set in 1979, by over five feet, observed crests at most other forecast locations on the Red River were approximately two feet above the previous record.

The interagency disaster survey team is examining all components of the National Weather Service's performance related to the recent floods on the Red River of the North, from preparedness and coordination through service delivery to public response. Team members conducted dozens of interviews with customers and cooperating agencies, and reviewed volumes of NWS forecast products and Red River data. The team of experts, with representatives of the U.S. Geological Survey and U.S. Army Corps of Engineers, includes hydrologists, meteorologists, an engineer, a social scientist from the academic community and a public information specialist.

The complete disaster survey report on the Red River of the North, including results of a hydraulic analysis and a more-detailed list of findings and recommendations, will be published in the months following further study and interagency coordination.

The National Weather Service's mission is to protect lives and prevent property damage by warning of impending hazardous weather conditions through its national network of weather forecast offices and river forecast centers. The NWS' performance is routinely evaluated after catastrophic weather-related events such as floods, hurricanes and tornadoes.