Shadyside Ohio Flooding, June 14, 1990

General Overview

Information from Natural Disaster Survey Report (Jan, 1991: U.S. Dept of Commerce, NOAA, NWS, Silver Spring, Md)

A deadly flash flood occured in eastern Ohio near the town of Shadyside on the evening of June 14, 1990. Over 3 inches of rain (precip analysis) fell along Pipe and Wegee Creeks in a short period of time (under 2 hours). There were 26 known deaths in Ohio during this event, of which 24 were along Pipe and Wegee Creeks with the remaining 2 along the Cumberland Run about 8-10 miles west/northwest of Shadyside.

With the rain falling in such a short amount of time, witnesses reported a wall of water between 10 and 30 feet rapidly moving downstream about 45 minutes after the onset of the heavy rain over the headwaters. Runoff was enchanced due to a very wet spring. Rainfall during May was 200 percent of normal. One resident described a sheet of water, ankle deep, running down the hill side near his house.

Shadyside is located in the western foothills of the Appalachians and characterized by small hills with steep slopes and narrow valleys. Most residents lived along the narrow flat land along the creek, adding to the potential danger. About 80 houses were completely destroyed, 79 sustained major damage and 172 houses sustained minor damage.

Meteorological Conditions

Synoptic scale conditions were favorable for development of showers and thunderstorms with heavy rain. At 500 mb, a large trough was present in the western U.S. with a corresponding ridge in the east. An weak shortwave was present on the backside of the ridge near Illinois. This pattern, we now know, is favorable for heavy rain and flash flooding.

At lower levels, tropical air (abundent moisture) was in place over western Ohio, with a moist tropical flow of air orignating from the Gulf of Mexico. Precipitable water amounts were over 1.75" and percent of normal ranged from 180 to near 200%.

On June 13, a large complex of showers and thunderstorms formed to the west of Ohio, producing a outflow boundry oriented southwest-northeast over western Ohio. A second east-west boundry moved southward into eastern Ohio and western Pennsylvania on June 14. This second boundry produced the mesoscale forcing for thunderstorm development. Thunderstorms began to form before 7 pm that evening and rapidly developed. Thunderstorms built backward (towards the southwest) allowing for multiple storms to move along the same track (training). Rainfall rates were further enhanced as two thunderstorms merged over the headwaters.

Hydrologic Conditions

Very heavy rain fell in 2 small basins on the night of June 14. Wegee (11.75 square miles) and Pipe (12.6 square miles) Creeks produced a wall of water ranging from 10 to 30 feet rapidly moving downstream, destroying everything in its path. Flood crests on the Wegee Creek occured at about 9:30 pm at a point 5 miles upstream and between 9:45 and 10:00 pm at the mouth (inferred from interviews). This would mean that the flood wave reached speeds of about 10 mph. Water flowing at this rate is difficult to outrun on foot. The crest on the Pipe Creek was estimated to have occurred prior to 10:00 pm.

No residents in either basin had rain gages. The only rainfall estimated came from the upper Wegee Creek wher 4-5 inches of rain was accumulated in a child's wading pool. The county sheriff recieved an unofficial report of 3.5" in 30 minutes in Morristown, 15 miles northwest of Shadyside.

Peak discharge was estimated at 13,000 cubic feet per second (cfs) for Wegee Creek and 15,000 cfs for Pipe Creek. Time to crest from the beginning of the rise to the crest was estimated at 40 min for Pipe Creek and 48 min for Wegee Creek. The speed was estimated between 10 to 15 feet per second.