At first, Jason Jarinko and the others didn't believe what a student at Central Columbia High School in Bloomsburg, Pa., told them.

"We just kind of scoffed that he had seen a bird or something," the teacher said.

Then they all saw the big white blimp, gliding about 300 feet above the school.

The unmanned Army surveillance blimp broke free from its tether in Maryland about 12:20 p.m. Wednesday. It floated about 150 miles over Pennsylvania in about 31/2 hours, finally grounding itself in a clump of trees about 80 miles north of Harrisburg.

Along the way, the 243-foot-long helium-filled craft dragged its tether line, a 6,700-foot-long cable that took out power lines as it drifted by.

"My first thought was Vo-Tech was doing something at the school, until my friends tagged on Facebook about the blimp," said Wendy Schafer of Bloomsburg.

After landing in the trees, the blimp, which cannot be controlled remotely, was secured, and the military arrived to reclaim it.

About 27,000 residents lost power during the day, state officials said. Bloomsburg University closed and canceled afternoon classes due to the outages. Outages were most severe in Columbia and Schuylkill Counties, according to Gov. Wolf's office.

Two F-16 Fighter jets from the Atlantic City Air National Guard Base scrambled to track the 7,000-pound aircraft. It detached amid wind and rain from its mooring station at the Aberdeen Proving Ground, according to the North American Aerospace Defense Command. How the blimp got loose has yet to be disclosed.

Such blimps have many uses, including monitoring U.S. bases in Iraq and Afghanistan.

610-313-8207 @MichaelleBond

This article contains information from the Associated Press.