Heavy Rain, Berks
- When
- April 9, 5:00 AM EST to April 10, 4:00 AM EST
- Where
- Berks County, Countywide
- Coordinates
- 40.416, -75.926 (the zone’s center; the record gives no point)
Flash Flooding and Heavy Rain in Pennsylvania, April 9 to 10, 1998
A low pressure system moved into the central Ohio River Valley the morning of the 9th. Its associated warm front extended east into the Delmarva Peninsula.
Where it happened
Every event with a place to put it; 10 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 10
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 PHI wrote it up.
A low pressure system moved into the central Ohio River Valley the morning of the 9th. Its associated warm front extended east into the Delmarva Peninsula. A second low pressure system developed along this boundary on the Delmarva Peninsula the evening of the 9th and moved rapidly offshore the morning of the 10th. Rain overspread Southeast Pennsylvania the morning of the 9th, but fell at its heaviest during the afternoon and evening of the 9th. Light rain lingered into the morning of the 10th. Storm totals averaged between 1.5 and 2.0 inches with some locally higher amounts especially in Montgomery County. The heavy rain caused flooding along some of the streams in Montgomery and Chester Counties as well as the usual urban and poor drainage flooding. In Chester County, the Valley Creek near Valley Forge briefly crested above its estimated 7 foot flood stage around 8 p.m. EDT. In Montgomery County, the Perkiomen Creek in Schwenksville reached its estimated flood stage of 7 feet at 11 p.m. EDT. It crested at 7.4 feet at 2 a.m. EDT and was back within bankfull at 4 a.m. EDT. The Manatawny Creek flooded in two locations. At Spangsville (in Berks County), it crested and remained at its estimated flood stage of 6 feet from 2 a.m. through 4 a.m. EDT on the 10th. At Pottstown (in Montgomery County), the Manatawny Creek reached its estimated flood stage of 4.5 feet at 2 a.m. EDT on the 10th, crested at 4.9 feet at 5 a.m. EDT and was back within bankfull at 8 a.m. EDT on the 10th.Storm totals included 2.75 inches in Green Lane (Montgomery County), 2.67 inches at the Easton Bridge (Northampton County), 2.19 inches in Fricks (Bucks County), 2.07 inches at the Lehigh Valley International Airport, 2.01 inches in Perkasie (Bucks County), 1.98 inches in Doylestown (Bucks County) and the Blue Marsh Dam (Berks County), 1.90 inches in Hamburg (Berks County) and Neshaminy Falls (Bucks County), 1.89 inches in Valley Forge (Montgomery County), 1.77 inches in Palm (Montgomery County), 1.72 inches in Reading (Berks County), 1.71 inches at the Northeast Philadelphia Airport, 1.65 inches in Glenmoore (Chester County), 1.64 inches in Norristown (Montgomery County), 1.61 inches in Exton (Chester County), 1.52 inches in Crum Creek (Delaware County), 1.50 inches at the Franklin Institute within Philadelphia and 1.02 inches at the Philadelphia International Airport.
The radar
The Philadelphia radar (KDIX), 139 km away, was scanning. The volume nearest the first event began at 09:57 UTC.
Event by event
8 heavy rain, 2 flash flood. Local standard time, as filed.
Heavy Rain, Lehigh
- When
- April 9, 6:00 AM EST to April 10, 5:00 AM EST
- Where
- Lehigh County, Countywide
- Coordinates
- 40.613, -75.592 (the zone’s center; the record gives no point)
Heavy Rain, Chester
- When
- April 9, 7:00 AM EST to April 10, 6:00 AM EST
- Where
- Chester County, Countywide
- Coordinates
- 39.973, -75.748 (the zone’s center; the record gives no point)
Heavy Rain, Northampton
- When
- April 9, 7:00 AM EST to April 10, 6:00 AM EST
- Where
- Northampton County, Countywide
- Coordinates
- 40.754, -75.307 (the zone’s center; the record gives no point)
Heavy Rain, Bucks
- When
- April 9, 8:00 AM EST to April 10, 7:00 AM EST
- Where
- Bucks County, Countywide
- Coordinates
- 40.337, -75.107 (the zone’s center; the record gives no point)
Heavy Rain, Delaware
- When
- April 9, 8:00 AM EST to April 10, 7:00 AM EST
- Where
- Delaware County, Countywide
- Coordinates
- 39.917, -75.399 (the zone’s center; the record gives no point)
Heavy Rain, Montgomery
- When
- April 9, 8:00 AM EST to April 10, 7:00 AM EST
- Where
- Montgomery County, Countywide
- Coordinates
- 40.211, -75.367 (the zone’s center; the record gives no point)
Heavy Rain, Philadelphia
- When
- April 9, 8:00 AM EST to April 10, 7:00 AM EST
- Where
- Philadelphia County, Countywide
- Coordinates
- 40.008, -75.134 (the zone’s center; the record gives no point)
Flash Flood, Chester
- When
- April 9, 6:45 PM EST to 7:15 PM EST
- Where
- Chester County, Valley Forge
- Coordinates
- 39.973, -75.748 (the zone’s center; the record gives no point)
Flash Flood, Montgomery
- When
- April 9, 10:00 PM EST to April 10, 7:00 AM EST
- Where
- Montgomery County, Schwenksville
- Coordinates
- 40.211, -75.367 (the zone’s center; the record gives no point)
What these are
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
- 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
- Tornadoes in Georgia, April 9, 1998
- Tornadoes in Georgia, April 9, 1998
- Tornadoes and Flash Flooding in Georgia, April 9 to 17, 1998
- Damaging Winds in New York, April 9, 1998
- Rip Current in Alabama, April 9, 1998
- Storm Surge in Ohio, April 9 to 10, 1998
- Flooding in Michigan, April 9 to 10, 1998
- Tornado and Hail in Virginia, April 9, 1998
- Tornado and Hail in South Carolina, April 9, 1998
- Blizzard and High Wind in Alaska, April 9 to 10, 1998
- Flash Flooding in North Carolina, April 9, 1998
- High Wind in Hawaii, April 9 to 11, 1998
More
Every storm in Pennsylvania in 1998Every state in 1998This day in weather historyWarnings in Pennsylvania, April 1998
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: 5643461, 5643465, 5643463, 5643467, 5643462, 5643464, 5643466, 5643468, 5643469, 5643470.