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.
