Pennsylvania, 2000

Flash Flooding in Pennsylvania, August 6 to 7, 2000

August 6 to 7, 2000 · NWS PBZ · 3 events in 3 counties and zones

During the morning and afternoon hours of the 6th, strong thunderstorms produced between 2 and 4 inches of rain across Allegheny, Washington and Westmoreland Counties. Throughout the evening of the 6th and the early morning hours of the 7th, more thunderstorms formed and trained along a west-to-east line over these counties.

Where it happened

Every event with a place to put it; 3 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
$11 million
Crop damage
None recorded
Events
3

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.

What happened

The episode as NWS PBZ wrote it up.

During the morning and afternoon hours of the 6th, strong thunderstorms produced between 2 and 4 inches of rain across Allegheny, Washington and Westmoreland Counties. Throughout the evening of the 6th and the early morning hours of the 7th, more thunderstorms formed and trained along a west-to-east line over these counties. These thunderstorms produced another 2 to 3 inches of rain across this area. Final rainfall totals for this event in Allegheny County include 5.71 inches at the Allegheny County Airport in West Mifflin (4.27 inches through midnight, plus another 1.41 inches during the early morning hours of the 7th), 5.55 inches in Baldwin Borough, 5.25 inches in Castle Shannon and 4.3 inches in Pleasant Hills. The Pittsburgh International Airport set a record for the 6th, recording 1.59 inches of rain. In Washington County, 3.4 inches of rain were recorded in Burgettstown from this event, and 3.2 inches in the city of Washington. In Westmoreland County, 3.3 inches fell in Jeanette, with 3.2 inches recorded in both Derry and Murrysville. Several other locations across these counties recorded rainfall ranging between 2 and 3 inches.

The radar

The Pittsburgh radar (KPBZ), 21 km away, was scanning. The volume nearest the first event began at 02:33 UTC.

Open the radar archive at this moment

Event by event

3 flash flood. Local standard time, as filed.

Flash Flood, Allegheny

When
August 6, 9:35 PM EST to August 7, 10:00 AM EST
Where
Allegheny County, Countywide
Property damage
$10 million
Reported by
NEWSPAPER
Coordinates
40.469, -79.981 (the zone’s center; the record gives no point)

Widespread flash flooding problems were reported across the county, with 51 of the county's 130 municipalities reporting some degree of storm impact. Of those 51 municipalities, 15 reported significant impact, including flooding of streets and basements, washed-away property and cars, and roadway infrastructure damage. An estimated 1200 homes and businesses in those 51 communities were impacted. The Allegheny County Chief Executive's office reported the hardest-hit communities were Baldwin, Brentwood, Hays, Mt. Lebanon, West Mifflin, and the City of Pittsburgh along the Route 51/88 corridor. The town of Hays was probably the hardest hit of all the communities, with over 75 homes and 20 commercial properties reporting heavy damage. Several cars were swept away by the floodwaters, forcing the rescue of several people who were trapped in the vehicles. The water even swept away a pleasure boat parked in a private driveway. Emergency officials also rescued several people trapped in their homes by the high water. In McKeesport, a car dealership along State Route 48 saw a 3- to 4-foot high wall of water and mud ruin 35 to 40 new cars -- an estimated $2 million dollar loss. Several businesses in downtown McKeesport, along with City Hall, received minor water damage. At The Marina at McKees Point, 16 boats were lost and a pier buckled. Elsewhere across the county, numerous reports of flooded basements, stream flooding and mudslides were received throughout the evening of the 6th and early morning hours of the 7th.

Flash Flood, Westmoreland

When
August 6, 10:14 PM EST to August 7, 7:00 AM EST
Where
Westmoreland County, Countywide
Property damage
$500,000
Reported by
NEWSPAPER
Coordinates
40.311, -79.467 (the zone’s center; the record gives no point)

Widespread flash flooding was reported across Westmoreland County with western parts of the county, in particular the Monessen, Jeanette, Smithton, Jacobs Creek and Belle Vernon areas, reporting the most problems. In Harrison City, the fire department received 30 requests for basement pumping from the flooding. County officials reported the hardest hit area was the Elks Creek housing development in Rostraver Township, where 3 homes were destroyed and 12 more needed to be evacuated. State Emergency Management officials estimate that across the county, 2 homes were destroyed, 25 homes received major damage, 60 homes receive minor damage, 3 apartment buildings received minor damage and 6 businesses were impacted. The Red Cross estimated that around 40 families were forced from their homes by the flooding.

Flash Flood, Washington

When
August 7, 12:40 AM EST to 7:00 AM EST
Where
Washington County, Countywide
Property damage
$500,000
Reported by
NEWSPAPER
Coordinates
40.189, -80.248 (the zone’s center; the record gives no point)

In Washington County, the flooding from the storms damaged 250 homes or buildings. According to county officials, the McDonald, Midway and Charleroi areas were the hardest hit. In the Mount Pleasant area, 20 families were evacuated from their homes due to the threat of flooding. County officials were forced to close 10 roads during this event, and a mudslide on State Route 88 near Fredericktown kept that road closed until well into the day on the 7th.

What these are

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 2000Every state in 2000This day in weather historyWarnings in Pennsylvania, August 2000

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: 5175137, 5157285, 5157286.