Police reported to a Northeast Philadelphia neighborhood Saturday night after witness reported a mysterious object had fallen from the sky and crashed down onto a parked car. A bomb squad arrived promptly after the call, but they found nothing but a white object attached to a small parachute, which turned out to be a weather balloon.
The instrument — called a radiosonde — had been carried skyward by a balloon to measure temperature, pressure and humidity and transmit data to weather forecast centers. They're launched daily from nearly 100 stations in US states and territories; this one was reportedly from the National Weather Service in Sterling, Virginia, according to the Washington Post — 165 miles from where it caused such a ruckus in Philly.
According to some reports, it could have been strong winds that steered the balloon so far off course.
Weather Balloon(RadioSonde) from @NWS_BaltWash falls in Philadelphia, prompts bomb scare. https://t.co/ZyF6s4Unpq pic.twitter.com/quUvgHql1L
— Brad Panovich (@wxbrad) November 23, 2015
"The great majority land uneventfully," said Chris Strong, warning coordination meteorologist for the D.C. NWS office. "But once in a great while you hear about something like this."
"Several years ago," Strong commented, "two landed on the White House grounds within a few days of one another. They go up and come down, and occasionally in a place where we'll hear about it."
According to the NWS, around 70,000 weather balloons are launched every year.