Information from Natural Disaster Survey Report (Jan, 1991: U.S.
Dept of Commerce, NOAA, NWS, Silver Spring, MD)
A deadly flash flood occurred in eastern Ohio near the town of
Shadyside on the evening of June 14, 1990. Over 3 inches of rain
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 enhanced 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
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
short wave 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 (abundant moisture) was in place
over western Ohio, with a moist tropical flow of air originating
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 boundary oriented southwest-northeast
over western Ohio. A second east-west boundary moved southward into
eastern Ohio and western Pennsylvania on June 14. This second boundary
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.
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
occurred 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 were 4-5 inches of rain
was accumulated in a child's wading pool. The county sheriff received
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.