Major power outage in Michigan's Upper Peninsula

MARQUETTE, Mich. (AP) - A lightning strike disabled two transmission lines that serve Michigan's central and western Upper Peninsula, leaving tens of thousands without power Tuesday.

Numerous schools were closed and some businesses idled, including the Tilden and Empire iron mines in Marquette County. Crews in helicopters and on foot were inspecting the power lines and towers for damage while others worked to restore electricity to darkened homes.

The lightning bolt hit two lines that transmit power between Oconto Falls, Wis., and Kingsford, Mich., about 3:30 a.m., said Anne Spaltholz, spokeswoman for American Transmission Co., which owns and operates the lines.

With another line in the area down for maintenance, a large swath of the Upper Peninsula was without power, from Munising to Escanaba and west to the Keweenaw Peninsula.

"Essentially we had a blackout," Spaltholz told The Mining Journal of Marquette.

The outage affected more than 50,000 customers served by Upper Peninsula Power Co., spokeswoman Lisa Prunty said. Also knocked out were about 27,000 customers of We Energies, although power had been restored to nearly all of them by 8 a.m., spokesman Brian Manthey said.

With three key lines out of service, the system became unstable and triggered the shutdown of Presque Isle Power Plant in Marquette, which supplies the iron mines.

They had enough power to keep the lights on in their offices but were unable to process iron ore, said Dale Hemmila, spokesman for Cliffs Natural Resources, which operates the mines.

"To run these operations we average 270 megawatts on a daily basis and we're nowhere near that right now," Hemmila said early Tuesday afternoon. The company was expecting to be shut down from eight to 16 hours, he said.