A massive white smoke cloud that moved through the Philadelphia area yesterday, prompting residents to call local fire departments, was indeed coming from a fire - in Canada.
The 800-mile-long plume of acrid, chalk-colored haze originated from a large area of forest fires in central Quebec, Dean Iovino, a meteorologist at the National Weather Service, said.
"It's actually a series of clouds that has spread south," Iovino said.
The cloud arrived in the area about midday, he said. By 5 p.m., it had spread as far west as Buffalo and Erie and as far south as southern New Jersey and northern Delaware.
The cloud was expected to move out of the area by about noon today by shifting winds, Iovino said.
Fire departments in Montgomery and Bucks Counties reported calls from worried residents yesterday. In Montgomery County, calls began coming in about 3:30 p.m., John Scheiter, assistant fire chief of the Colmar Fire Department, said.
"People were reporting odorous smoke," he said. "It kept us busy, that's for sure."
Scheiter said his department was called to the area of the Montgomeryville Mall along Route 309, but had been unable to locate a fire. Fire departments in Hatfield, Upper Gwynedd and Lansdale also received reports of the cloud and sent personnel out to investigate, he said.
A fire official in Bucks County said several calls came in from the Upper Bucks area and fire personnel were dispatched.
The haze affected visibility temporarily, causing the Williamsport Flight Station, which briefs pilots flying in eastern Pennsylvania, to issue an advisory.
A weather briefer at the station said visibility was reduced from the ground up to about 14,000 feet. The advisory was expected to be in effect until about 7 p.m., he said.
Molly Renner, a pilot and receptionist at the Doylestown Airport, said the haze was not severe enough to shut down operations. Pilots still were able to use visual flight readings, she said.
In some places along its path, the cloud was so thick it obscured the sun. The heaviest cover occurred in the area around Syracuse and Watertown, New York, yesterday morning.
Iovino, of the weather service, said such a phenomenon is unusual. The last incidence he could recall of a smoke mass traveling such a distance occurred about 15 years ago, when a Kentucky fire sent a large cloud into the Philadelphia area.
The fires in Quebec were sparked by lightning and thunderstorms last week, the weather service said. As winds shifted Friday, the smoke began traveling south into New York and parts of New England and west to Detroit.
Contact Cynthia McGroarty at 610-313-8113 or cmcgroarty@phillynews.com.