Update 4:40 p.m.: The storm did bring a tornado to Delaware, NWS announced, about 100 miles south of Philly.

Philadelphians who were jolted awake by a tornado warning Monday morning may be wondering: Was there really any danger — enough to merit an alert sent out at 3:20 a.m.?

Yes, according to weather officials. Philly is not in an area of the U.S. that gets storm funnels on the regular, like the Great Plains. But they do happen in the Mid-Atlantic, and can cause a lot of damage.

By 8 a.m. Monday, many damage reports had rolled in. High winds caused overturned trees, some downed power lines caused outages, and flooding created traffic snarls. In Camden, two rooftops were reported torn off.

There were no actual tornadoes spotted near Philly, according to early National Weather Service reports, but there was one recorded in Sussex County, Delaware.

“Tornadoes are a form of severe weather,” Philadelphia Office of Emergency Management spokesperson Jeffrey Kolakowski told Billy Penn, “[but] we also see severe weather like thunderstorms and straight line winds that can have the same effects.”

The most recent tornado in the region touched down near Honey Brook in Chester County in June 2015, though newscasters carefully refrained from using the t-word until after the cloud formation had passed. It ended up being classified as a moderate tornado, Category F1 in the Fujita Tornado Intensity Scale.

(The word “moderate” here is relative: F1 tornadoes are described as being able to peel surfaces off roofs, overturn mobile homes and push cars off roads.)

In Philadelphia proper, the last hit was a gale tornado in 2011, which swept down Red Lion Road in Northeast Philly for a few seconds and injured at least two people. It was rated F0, meaning its winds did not exceed 72 mph.

Category ratings don’t always tell the whole story. An F0 tornado that struck Marconi Plaza in 1999 injured 18 people, while an F2 in Bustleton the previous year didn’t see any reported injuries. Previously Philly has recorded tornadoes in 1991, 1989, 1985, 1978 and 1958.

This time around, the possibility of a tornado was first noted by NWS on Sunday afternoon, more than 12 hours before the alert went out. The Mount Holly NOAA station issued a special threat advisory, noting that severe weather is especially dangerous at night.

Philadelphia’s Office of Emergency Management issued its own alert via the free ReadyPhiladelphia service. To be added to the list, text READYPHILA to 888-777.

OEM had been doing what it calls “enhanced monitoring” all day on Sunday in conjunction with the 24/7 Regional Integration Center, so it was ready to coordinate with police and fire emergency dispatch to monitor impact and damage in real time, per spokesperson Kolakowski. “There were responses for trees/wires down. PECO did not report widespread outages.”

Next week happens to be Severe Weather Awareness Week in Pennsylvania, he added, so expect to see lots more content about warnings and alerts.

Once people were woken up by the alert, Philly Twitter turned into an early morning tornado party.


Meanwhile, Midwesterners had a good chuckle.

Danya Henninger is director and editor of Billy Penn at WHYY, where she oversees the team, all editorial decisions, and all revenue generation — including the membership program. She is a former food...