UPDATE: More than 20,000 still without power in Wisconsin
More than 20,000 customers were still without power Friday morning and Wisconsin Public Service Corp. warned that some "should prepare for days without power."
The utility told Newsline 9 they expect power to be out for some until Saturday.
A thunderstorm that rumbled across much of northern Wisconsin Thursday packed 70 mph winds, heavy downpours and frequent lightning, knocking out power to about 50,000 customers, the utility said.
WPS facilities suffered extensive damage, including broken poles and downed lines, the utility said.
"Restoration times are nearly impossible to predict," the utility said in a statement. "It now appears that some customers should prepare for days without power before all the outages can be repaired."
Minocqua, Rhinelander, Crivitz and Ellison Bay were the hardest hit areas, WPS said.
The utility said it had all available crews working and was getting help from contractors. They told Newsline that 80 contractors are headed out to work to restore power and many will work through the night.
They remind customers of some safety issues while power is out. They advise customers not to cut or remove down trees or branches unless you are sure power lines are not involved, be stocked with batteries, bottled water and non-perishable food, and test storm equipment regularly.
If you want to report an outage, call WPS at 1-800-450-7240.