Laserfiche WebLink
<br />Flood of May-June 1894. Heavy rains fell on 19 May - 2 June over the mountains <br />and plains extendinll from the Colorado-Wyoming border southward into the Republican <br />and Arkansas River basins, 'Rainfall amounts over the high plains gradually decreased <br />from west to east varying from 5 inches at Boulder to approximately 2,5 inches at the <br />mouth of Boulder Creek. <br /> <br />Flood of June 1921. Heavy general rainfall occurred from 2 June - 6 June over the <br />South Platte River basin with the greatest amounts along the foothills of the Rocky <br />Mountains. Rainfall covered an area of approximately 520 square miles. The maximum <br />recorded rainfall WSIS 5.29 inches and the greatest recorded rainfall intensity was 4.3 <br />inches in 6 hours at Longmont. Rainfall totaled 3.36 inches at Boulder. <br /> <br />Flood of August-September 1938, Heavy rainfall occurred from 31 August to 4 <br />September over all of eastern Colorado. Boulder reported 3.36 inches of precipitation from <br />31 August to 4 September with 2.32 inches falling during 2 September. <br /> <br />Flood of August 1951. On the afternoon and evening of 3 August. very heavy rainfall <br />occurred along 50 miles of the Front Range and foothills from Boulder to Fort Collins. <br />Unofficial reports indicated 6.3 inches of precipitation occurred near Lyons and more than <br />6 inches occurred southwest of Niwot. A flood peak determination of 5,700 cfs on Dry <br />Creek was obtained about 1.5 miles south of Niwot. The crest of the flood occurred about <br />9:50 p.m. on 3 Au!~ust. The flood swept across U.S. Highway 287, 2 miles south of <br />Longmont, at about 10:45 p.m, The flood on Dry Creek, which was 1/4 miles wide in <br />places. swept away crops, buildings, and equipment and required the evacuation of about <br />50 people. Railroad and highway embankments and bridges were washed out. <br /> <br />Flood of May 1969. Heavy rainfall with a relatively long duration occurred from 4 May <br />until 8 May. The storm covered an area along and near the eastem Slopes of the Rocky <br />Mountains and extElIlded into portions of the high plains. The heaviest amounts were <br />centered 25 miles southwest of Denver and extended In a band along the foothills of the <br />Rocky Mountains nc'rthward of Estes Park. Rainfall amounts of 7.60 inches were reported <br />at Boulder. <br /> <br />Flood of May 1973. Rainfall generally ranging to as much as 6 inches fell on the plains <br />east of the Rocky Mountains beginning on 5 May. The Dry Creek basin received amounts <br />ranging from 2 to 4 inches. Runoff from this general storm contributed to considerable <br />flOOding on the South Platte River. <br /> <br />4.8 LEFT HAND CREEK <br /> <br />Flood Historv. Left-Hand Creek floods are most frequently produced by intense rainfall <br />during thunderstorms. Snowmelt runoff combined with runoff from spring rains of long <br />duration also produce high stream flows. The former are characterized by a high peak <br />discharge of short (juration. The latter usually have lesser peak discharges and are of <br /> <br />Colorado Flood <br />Hydrology M'lnual <br /> <br />4.12 <br /> <br />a:w=r <br />