FLOOD06533 - Laserfiche WebLink

Home Browse Search

Colorado Flood Hazard Mitigation Plan -1999 boundary to over 70 in the mountains along the Front Range, The thunderstorm flood season in Colorado is from the middle of July through October. Big Thompson Flood (1976) - The widely publicized Big Thompson Canyon flood disaster of July 31, 1976, was a resutt of an intense thunderstorm cell that dropped up to 10 inches of rain in a few hours over the basin. 1993 Floods - On May 15-16, 1993, a thunderstorm- induced flood event occurred at Rifle on R~le and Gov- emment creeks, As is usually the case, the highest flows in the shortest period of time occurred when an estimated 125-year flood discharge Impacted R~le, Structures and vehicles in harm's way suffered dam- ages in excess of $200,000, On June 17, 1993, a flash flood occurred on Shooks Run In Colorado Springs, Damages were confined to a mobile home park on the creek's edge with losses esti- mated at $1 Million, In July 1993, the Town of Otis and the unincorporated area of Cope in Washington County and the City of Yuma in Yuma County experienced a weekend flood event as a result of three consecutive days of thunder- storms, Several homes suffered damages and road- ways were inundated with loss in excess of $650,000, In Otis, a flood control and storm drainage project pro- tecting the northern ha~ of town worked, On August 10, 1993, flash floods occurred on several creeks in Delta County, Two roads were washed out and a flood fight was oonducted with sandbags on Ro- bldeaux Creek near the Department of Corrections Detention Faciltty, On August 26-29, 1993, general rainstorms caused flooding in Archuleta and La Plata counties, A subdivi- sion in Archuleta County was threatened and roads damaged as the Rio Blanco overflowed lis banks south of Pagosa Springs, In Durango, the Fire Department had their emergency operations plan in effect and came very ciose to evacuating residents of a mobile home park on the Animas River. 1995 Floods - In the spring and early summer of 1995, the lower South Platte, the lower Arkansas and the Roaring Fork Rivers were impacted by significant flooding, Most damages were experienced by agricul- turallandowners, 1997 Floods - On July 24-28, 1997, the City of Fort Collins and most of eastern Colorado received soaking andlor drenching rains, adding to soil moisture in some locations, As the cold front arrived in the late afternoon of July 27th, strong thunderstorms developed just north and west of Fort Collins, Later that night, steady rains developed along the eastern base of the foothills in Larimer County and continued until about noon on July 28th, Several inches of new rain were reported just west and northwest of Fort Collins totally saturat- ing the ground, producing major flooding in Laporte, and setting the stage for the evening flood event. On the evening of July 28, 1997, intense rains began around 6,30 p,m, in the foothills west of Fort Collins, Winds from the east and southeast continued to pump moisture into the storm system throughout the eve- ning, The oore of the storm was very small but re- mained nearly stationary over the headwaters of Spring Creek, the Fairbrooke Channel, Clearview Channel, the CSU Drainage Basin, and the West Vine Drainage Basin, Rainfall intensity increased and reached a maximum between 8,30 p,m, and 10:00 p, m, before ending abruptly, A subsequent analysis of rainfall oonducted by CSU showed a maximum of 10,2 inches of rainfall in less than five hours near the inter- section of Drake Rd, and Overland Trail. On July 29, 1997, slow-moving thunderstorms dumped large amounts of rainfall over the Pawnee Creek Basin Colorado Flood Facts Counties/CitiesITowns with Flood Prone Areas Population of 100-Year Floodplain 268 250,000 Homes in 100-Year Floodplain 65,000 15,000 $11 Billion $ 3.3 Billion CommercialllndustriallBusinesses in 100-year Floodplain Total Value of Property in 100-Year Floodplain Cumulative Flood Losses from Turn of Century to 1999 Source: CWCB Figure 2.3 Chapter 2 - 4 1212319910,00 PM