Montco Tornado: Where It Touched Down, Scale Rating Released

MONTGOMERY COUNTY, PA — An investigation from the National Weather Service detailed the strength and location of the tornado that hit Montgomery County during Tropical Storm Isaias. It was one of two tornadoes that hit the region amid heavy rainfall, widespread power outages, and historic flooding on Tuesday, as another touched down in Bucks County.

The tornado first touched down in Worcester Township, near the intersection of Brindle Court and Township Line Road, authorities said. This occurred at around 11:15 a.m.

A few small trees were taken down in the residential area near there. It continued to progress northwest through Worcester, taking more trees down on Potshop Road before moving on in a more destructive pattern to Valley Forge Road and further northwest along Heebner Road, up to the intersection with Shefley Lane.

>>Montco Declares Disaster Emergency; 1 Person Remains Missing

The last sign of damage from the tornado was on Hollow Road, where several hardwood trees were taken down, as well as multiple utility lines, the National Weather Service said.

Officials classified it as an "EF0" on the Enhanced Fujita Scale. EF0 is the lowest ranking of tornado, indicating winds between 65 and 85 miles per hour. Officials had previously noted a maximum wind speed of about 50 miles per hour in Upper Dublin, at the intersection of Route 309 and I-276, just after 1:30 p.m. Tuesday.

Local neighborhoods, creeks, and rivers were left scattered with debris, with mailboxes ripped down and unsecured items whipped through the area.

The progression and development of the tornado was seen as "unusual," according to NWS, because it developed ahead of the main center of Isaias in the region. An area of intense circulation tightened within a rainband in the southeastern part of Montgomery County, before intensifying and making landfall as it moved to the northwest.

The county declared a disaster emergency Wednesday. The storm left one child dead, and a woman remained missing Friday after being swept away in the Schuylkill River.

The Montgomery County Emergency Management Office, along with Skywarn spotter Lou Ruh, assisted the National Weather Service in the investigation and survey of the tornado.

There were two more tornadoes at the Jersey Shore during Isais, as well as tornadoes in. Kent and New Castle counties in Delaware and Queen Anne's County, Maryland.