Pennsylvania, 1999

Flash Flood and Hail in Pennsylvania, May 18 to 19, 1999

May 18 to 19, 1999 · NWS PBZ · 4 events in 3 counties and zones

2 thunderstorm wind, 1 hail, 1 flash flood, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$104,000
Crop damage
None recorded
Events
4

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

The radar

The Pittsburgh radar (KPBZ), 57 km away, was scanning. The volume nearest the first event began at 20:30 UTC.

Open the radar archive at this moment

Event by event

2 thunderstorm wind, 1 hail, 1 flash flood. Local standard time, as filed.

Thunderstorm Wind, Washington

When
May 18, 3:30 PM EST
Where
Washington County, Marianna
Measured
50 kt (58 mph)
Property damage
$3,000
Reported by
EMERGENCY MANAGER
Coordinates
40.030, -80.080

Thunderstorm winds downed several trees.

Thunderstorm Wind, Greene

When
May 18, 5:25 PM EST
Where
Greene County, Waynesburg
Measured
50 kt (58 mph)
Property damage
$1,000
Reported by
EMERGENCY MANAGER
Coordinates
39.900, -80.200

Thunderstorm winds downed a large tree.

Hail, Allegheny

When
May 18, 5:50 PM EST
Where
Allegheny County, White Oak
Measured
0.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
40.350, -79.800

Flash Flood, Allegheny

When
May 18, 5:56 PM EST to May 19, 1:00 AM EST
Where
Allegheny County, East Portion
Property damage
$100,000
Reported by
EMERGENCY MANAGER
Coordinates
40.469, -79.981 (the zone’s center; the record gives no point)

Torrential thunderstorm rains fell across eastern portions of Allegheny County, with up to four inches of rain measured in the Braddock area. North Braddock officials reported that Electric Avenue was flooded, with the water high enough to float a dumpster down the street. In Forest Hills, emergency workers reported that 20 people were evacuated from 10 homes along Kenmore Avenue. Turtle Creek officials reported a section of Route 130 was closed between Pitcairn and Turtle Creek after a mudslide. Flooded basements and power outages were reported in Turtle Creek, Munhall and McKeesport. Also in McKeesport, the W.D. Mansfield Bridge was shut down for several hours as approaches to the bridge were flooded by waters as deep as four feet. Minor street flooding was also reported in the nearby communities of Glassport and Port Vue. An area 911 dispatcher said "There are 33 fire and emergency medical service companies in the Mon Valley and they are all busy.".

What these are

Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Pennsylvania in 1999Every state in 1999This day in weather historyWarnings in Pennsylvania, May 1999

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5699140, 5699141, 5699142, 5699239.