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-2- The Flash Flood Warning for Salt Lake County was issued on Sunday, September 26, about 5 hours before any serious flooding was experienced. By mid afternoon flooding became severe along Big and Little Cottonwood Creeks. The heavy rainfall was centered along and downstream of these drainages. A record flow of 1,095 CFS was registered about 7:30 P.M. Sunday evening at Cottonwood Weir as Big Cottonwood Creek leaves the mountains and enters the Salt Lake Valley. The record spring snowmelt crest on Big Cottonwood was only 835 CFS on June 6, 1909. Little Cottonwood Creek peaked at 1,135 CFS around 2:00 P.M. Sunday afternoon with the previous record flow of 762 CFS on June 11, 1921. These creeks have a stream bed capacity of only 500 CFS. Record flooding in the past on these two creeks has been due to snowmelt, enhanced to a small degree by rainfall, but never entirely associated with heavy rains. Another natural phenomenon that enhanced the situation was the heaviest rains were over the two Cottonwood Canyons which are from 40 to 60 percent granite rock formation. Mill Creek just to the north of Big Cotton- wood Creek is nearly 100 percent dirt, trees, and shrubs. Mill Creek only rose to 46 CFS during the peak of the storm. Runoff from urban areas added to the problem as the record flows from these two main creeks reached the valley areas. By late in the after- noon and evening hours, the flooding became severe. It was estimated that Big and Little Cottonwood in the Salt Lake Valley contained flows of 1,300 to 1,600 CFS rampaging through creek beds which normally hold around 400 to 600 CFS. This was very difficult to judge because such a great volume of water was out of the channel. Additional Flash Flood Statements/Warnings were issued during Sunday afternoon, September 26, with emphasis placed on the severe nature of the flood situation and the additional problems of mud slides in the canyon along the Wasatch Front after one slide was experienced in Little Cottonwood Canyon. Many mud slides were later reported. As the flood waters roared through the central and southern portions of the Salt Lake Valley, the relentless rains continued. Hundreds of people were being evacuated from their homes, mainly those which were close to flooded streams. Flood waters did extensive damage to the Willow Creek Condominiums and Trailer Park in the Cottonwood Cove. Around 3:00 P.M. Sunday afternoon the flooding in Big and Little Cottonwood Creeks were at a volume such that the next problem would be the Jordan River that is primarily fed by Utah Lake. Salt Lake County was advised these record flows would reach the Jordan River in the early evening hours and could produce another serious problem. This information was re- layed to the Utah State Engineers Office, and the gates were closed about 7:00 P.M. Sunday evening. Salt Lake County and Salt Lake City opened their maintenance areas to the public by late Sunday afternoon and provided free sandbags to anyone that desired them.