Pittsburgh New Year?s Day meteor explosion equivalent to 30 tonnes of TNT, says Nasa

A meteor that caused an earthshaking boom over suburban Pittsburgh on New Year's Day exploded in the atmosphere with an energy blast equivalent to an estimated 30 tonnes (27,200kg) of TNT, officials said.

The National Weather Service in Pittsburgh initially responded, suggesting the most likely explanation was a "meteor explosion" as people took to social media in search of answers.

Nasa's Meteor Watch later confirmed the meteor blast in a Facebook post on Monday, saying a nearby infrasound station registered the blast wave from the meteor as it broke apart, causing sonic booms.

The data enabled an estimate of the energy released as equivalent to 30 tonnes (27,200 kilograms) of TNT.

"If we make a reasonable assumption as to the meteor's speed (45,000mph, or 72,400km/h), we can ballpark the object's size at about a yard in diameter, with a mass close to half a tonne," the agency said.

If not for the cloudy weather, it said, the fireball would have been easily visible in the daytime sky - maybe about 100 times the brightness of the full moon.

National Weather Service meteorologist Shannon Hefferan told the Tribune-Review that satellite data recorded a flash over Washington County shortly before 11.30am on Saturday and officials believed it was due to a meteor "falling through the atmosphere". Hefferan said a similar event occurred on 17 September in Hardy County, West Virginia.