(CNN) -- Emergency officials sifted through damage and debris scattered across roadways Saturday after a line of fast-moving storms and high winds swept through northwestern Wisconsin the night before, leaving at least one person dead and 39 others injured.
Three people were critically injured and a second person died, though not as a result of the storm, Burnett County spokeswoman Dawn Sargent said.
The storms also contributed to "widespread power outages" in a county with a population that normally swells to more than 80,000 people during the Fourth of July weekend.
Burnett County's typical population is about 17,000.
"We ask nonresidents to avoid the area because of the road closures and the presence of emergency crews trying to clear debris from the roadways," Sargent added.
Roughly three-quarters of the county have been affected, while its northern sections were more heavily hit.
The towns of Grantsburg, Washburn, Danbury and Web Lake were among the hardest-hit areas, said Wisconsin's emergency management spokeswoman Rhonda Reynolds.
"Last night we were working, and at about 7 o'clock the winds really picked up," said Carinna Coy, an employee at T-Dawgs restaurant in Grantsburg. "From what we could see today, there's a lot of trees that tipped over and a lot of roads that are closed.
"Main Street is a mess," she added.
A hardware store owner in neighboring Washburn described gusty winds, heavy rains and lightning that preceded power outages.
"Power's been out in parts of Washburn for most of the day, though they say that hopefully it'll be back soon," Nate Swiston of Washburn Hardware said.
An aerial survey of the region revealed storm damage to homes and downed trees throughout the region.
Officials said Saturday that they are focused on looking for trapped residents and distributing food, water and emergency medical supplies.
The American Red Cross also opened a meals station for the general public at the Grantsburg Middle School, Sargent said.
CNN's Joe Sutton contributed to this report.