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<br />Friday, July 12 <br /> <br />8:30 a.m.-10:00 a.m. <br /> <br />. <br /> <br />The 1996 February flood in the Willamette and Columbia Rivers was a regional rain induced <br />event. Prior to the flood, the winter months had had far above average precipitation for <br />November through January. During the last week of January and early February temperatures <br />were well below normal and snow covered the low lying Willamette Basin. Finally on February <br />3 and 4 the Willamette Basin experienced an ice storm. On February 5 temperatures increased <br />as much as 20 degrees Fahrenheit in two hours. The National Weather Service began <br />forecasting a regional rain event coming from the Pacific Ocean beginning February 6 and 7. <br />Because the ground had been saturated, then frozen, the ice and snowmelt accompanied by the <br />rain caused very sharp rises in the hydrographs in the Willamette Basin. <br /> <br />The National Weather Service River Forecast Center (RFC) in Portland, Oregon, provides the <br />quantitative precipitation forecasts (QPF) and inflow and streamflow forecasts for the Corps of <br />Engineers. The model used is ca11ed SSARR (Seasonal System and Reservoir Regulation <br />Model). The forecasts for the Willamette Ba3in were updated and run as often as four times <br />each day during the event. In general the forecast modeling was very accurate in the Wi11amette <br />Basin. Although the rise on the hydrograph was uncharacteristically fast, the SSARR model was <br />fairly accurate in the rise. The model was also very accurate in forecasting the timing of the <br />peak. From February 5 through the peak, the model consistently had the peak: of the Willamette <br />hydrograph near midnight on February 8. <br /> <br />During the flood Emergency Operations Centers (EOCs) were activated in all the districts of . <br />North Pacific Division. In the Portland District the activities included levee repair and <br />inspection throughout the flood as well as assistance to the city of Salem after the flood when <br />the city's water supply was contaminated. 1'he Corps provided reservoir operations so that <br />repairs to the system could be made. <br /> <br />This was a large event and there were difficulties in coordinating the Columbia River project <br />operations with the Willamette River projects' operations. Although the Willamette forecasting <br />and reservoir regulation seemed to be fairly smooth, the Columbia River Forecasting was not <br />as hospitable. There are major tributaries to the Columbia River that do not have winter-time <br />forecasting models. Also the Columbia Basin models cannot be initillli7ed at a time other than <br />0400 each day. During the graveyard the forecasts were often wildly different than the real-time <br />situation. These variations made reservoir regulations very treacherous. <br /> <br />Emergency Operations Centers (EOC) were set up at each of the district offices in the Pacific <br />Northwest. There were combined weather, reservoir status, and EOC status briefings twice <br />daily during the event and once daily after the peak had passed. Some special reservoir <br />regulations were required in the Willamette basin after the event to assist in recovery efforts. <br /> <br />Some of the lessons learned during this flood were about the validity of using forecast <br />regulations that were not initill1i7.ed properly. If an event of this magnitude should occur again <br />we will be more prepared to deal with the public and the press to disseminate information and <br />answer questions. <br /> <br />. <br /> <br />11 <br />