Water-Supply Paper 2502
Summary of Significant Floods in the United States, Puerto Rico, and the Virgin Islands, 1970 Through 1989
Summary of Significant Floods, 1970 Through 1989, by State or Territory
In addition to the specific flood data, this section provides a description of the hydroclimatology and a summary of significant floods for each State or territory in the United States. The summary of significant floods includes those with loss of life or excessive damage during the period 1970 through 1989. The floods that were in the top 5 percent of each streamflow-gaging station's record during this period are tabulated, and an estimated recurrence interval is provided along with other pertinent data. A map of each State or territory is supplied to locate the streamflow-gaging stations.
Oklahoma is located in the south-central United States east of the Rocky Mountains. The State's position relative to the Rocky Mountains has a substantial effect on its climate. The airmasses that bring moisture to the State originate in the Gulf of Mexico and, with certain airflow conditions, in the Pacific Ocean off the coast of Mexico. The airmasses that come into the State from the west are usually stripped of moisture by the Rocky Mountains, and as a result, mean annual precipitation increases from west to east across the State. Mean annual precipitation ranges from 16 in. in the extreme western part of the Oklahoma Panhandle to 56 in. in the southeast corner of the State (Paulson and others, 1991).
Oklahoma's latitudinal position also plays a significant role in the State's variable weather. During the winter, Oklahoma lies in the southern range of the polar jetstream and the northern range of the subtropical jetstream. Under the effects of the subtropical jetstream, daytime high temperatures can be in the 70°F range. Under the effects of the polar jetstream, nighttime temperatures can dip below 0°F. During the summer, the potential for severe thunderstorms, which include tornados and large hail, is great. Thunderstorms are created in warm, humid airmasses or along dry lines or cold fronts and can produce excessive rainfall and floods. Wintertime storms can produce excessive regional rainfall amounts. Remnants of hurricanes and tropical storms can produce excessive rainfall from late summer through the fall months.
On the basis of regionalization procedures that relate flood characteristics to watershed and climatic characteristics, factors affecting the magnitude of maximum discharges for streams in Oklahoma are drainage area, mean annual precipitation, and main-channel slope. The factors that are significant in urban areas also include the percentage of impervious area and percentage of area served by storm sewers (Tortorelli, 1997).
The flood of October 11-13, 1973, known as the "Enid flood," was caused by a locally intense thunderstorm that was centered over Enid. This storm produced the greatest urban rainfall on record in Oklahoma. Rainfall accumulations were 15 to 20 in. within a 100-mi² area; 12 in. fell in 3 hours. The discharges recorded on the Salt Fork of the Arkansas River at Tonkawa (station 07151000, fig. 58), Arkansas River at Ralston (station 07152500, fig. 58), and Turkey Creek near Drummond (station 07159000, fig. 58), were the largest of record. Damages totalled $78 million (Bingham and others, 1974; Tortorelli and others, 1991).
The flood of May 26-27, 1984, known as the "Memorial Day flood," resulted from a series of violent thunderstorms centered over Tulsa. The recorded 1-hour rainfall of 6.6 in. was exceeded only by that recorded in the "Enid flood"; some areas received more than 14 in. in 8 hours-an estimated 89,000 acre-ft of rain fell within Tulsa. Almost all of the urban streams had maximum discharges that exceeded the 100-year flood-insurance study discharges; one site had an estimated 2.5 times the published maximum. The flooding was localized but caused $180 million in damages and destroyed or damaged 5,500 homes and 7,000 vehicles (Bergman and Tortorelli, 1988; Tortorelli and others, 1991).
The flood of August 27-28, 1977, in West Cache and Blue Beaver Creeks in southwestern Oklahoma was the result of a severe thunderstorm; runoff was 2,210 (ft³/s)/mi² in the upstream reach of Blue Beaver Creek. Rainfall data indicated 24-hour totals of 12 in. immediately south of Cache and 4 to 8 in. in the surrounding areas; an area-weighted average rainfall of 7.7 in. fell during a 6-hour storm period within a 200-mi² area, illustrating the large quantity of water that can result from an Oklahoma thunderstorm. Damages were $1 million (Tortorelli and others, 1991).
Thunderstorms caused by the remnants of Hurricane Norma produced severe flooding in south-central Oklahoma during October 13-16, 1981. Record discharges were recorded on the Blue River near Blue (station 07332500, fig. 58), the Clear Boggy River, and several smaller creeks. About 10 percent of the streamflow-gaging stations in the State recorded significant discharges. Damages were $23.8 million (Buckner and Kurklin, 1984; Tortorelli and others, 1991).
Floods of October 17-23, 1983, affected several streams in central and southwestern Oklahoma. The remnants of Hurricane Tico supplied moisture on October 16-21, 1983, that contributed to record discharges on Deep Red Run near Randlett (station 07311500, fig. 58), Washita River at Anadarko (station 07326500, fig. 58), and at Alex (station 07328100, fig. 58), East Cache Creek near Walters (station 07311000, fig. 58), and Walnut Creek at Purcell (station 07229300, fig. 58); serious flooding was evident in the lower Washita River Basin. A total of 17 in. of rain fell on the Rush Springs area, with 24-hour totals greater than 8.5 in. Damages exceeded $12 million (Hauth, 1985; Tortorelli and others, 1991).
About 20 percent of the streamflow-gaging stations in Oklahoma recorded significant discharges during the flood of October 1986. Rainfall ranging from 10 in. in the southwest to 20 in. in the north fell across the State. The rainfall was caused by the remnants of Hurricane Paine. Record maximum discharges were recorded on the Cimarron River at Perkins (station 07161000, fig. 58), Baron Fork at Eldon (station 07197000, fig. 58), and Elk Creek near Hobart (station 07304500, fig. 58) (Hauth and others, 1989; Tortorelli and others, 1991).
Thunderstorms on May 27-28, 1987, climaxed 11 days of intense rains in central and southwestern Oklahoma, with 10 to 15 in. of rain falling on some areas. Floods during May 29-30 caused several substantial maximum flows, especially in south-central Oklahoma, with record maximum discharges at the Pauls Valley (station 07328500, fig. 58) and Dickson (station 07331000, fig. 58) gages. A record of more than 200 floodwater-retarding structures built by the Natural Resources Conservation Service had emergency spillway discharge. There was severe damage to the cities of Chickasha, Lindsay, and Pauls Valley (Hauth and others, 1989; Tortorelli and others, 1991).
The location of streamflow-gaging stations in Oklahoma that had significant floods for 1970-89 is shown in figure 58 by station. The specific data for each significant flood are listed in table 37. A significant flood is one that ranks in the top 5 percent of all annual maximum discharges for that station's period of record.
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