Most of the damage is in northwest Indiana. In Lake of the Four Seasons, many trees toppled in the strong winds. Homeowners are out assessing the damage Thursday. Some of the trees ended up on top of homes. Some sheds and garages were also destroyed by the wind. The storm also brought dangerous lightning to the area.
In Lemont, Ill., Melanie Dennis says her husband and three dogs were inside their rental home when lightning struck around 6 p.m. The bolt caused a fire, destroying everything . One of her dogs could not escape, dying in the flames.
All of this happened years after Dennis lost two daughters in a car crash and a motorcycle accident. One of her daughter's ashes was inside the home, now lost in the rubble.
Dennis says they didn't have time to buy renters insurance since they just finished moving into the home last week. She also says at first, the fire was not that large and she believes firefighters should have been able to put out the flames.
The Lemont fire chief says they were relying on water in trucks since the home is set far back on a gravel driveway with no hydrants in sight.
Authorities in Ohio reported early Thursday morning that high winds from possible tornadoes had damaged barns in the northwest and knocked out power in some areas in the center of the Buckeye State.
Meteorologists warned about the possibility of a weather event called a derecho, which is a storm of strong straight-line winds spanning at least 240 miles.
By early Thursday, a derecho hadn't developed. And Greg Carbin of the National Weather Service's Storm Prediction Center in Norman, Okla., said, "With each hour that goes by, it's less likely."
While the Midwest dodged a derecho, several tornadoes, large hail and flooding did some damage.
In the small town of Belmond, Iowa, about 90 miles north of Des Moines, Duwayne Abel, owner of Cattleman's Steaks & Provisions restaurant, said a tornado demolished part of the building. No one was in the restaurant at the time.
"I was, oh, 8 miles west of town and I looked toward town and I could see a funnel cloud, having no idea it was exactly where our restaurant was," Abel said. His wife and an employee were able to get out of the restaurant and sought shelter in a basement.
In Iowa, at least two businesses and a home were "completely damaged," authorities said. A storm ripped through a farm in rural Alexander, destroying a motor home. Tens of thousands of people across the Upper Midwest lost power.
In Wisconsin, authorities said thunderstorms packing heavy rain and high winds caused a Wal-Mart roof to partially collapse. Lake Delton Fire Chief Darren Jorgenson says two employees had minor injuries, but no customers were hurt.
"We're just happy that we don't have reports of injuries or fatalities," said Stephanie Bond with Iowa Homeland Security and Emergency Management. "We just hope the extent of the damage is minimal."
Even before the storms moved through, officials postponed Wednesday night's Chicago White Sox game against the Toronto Blue Jays and canceled a symphony concert at the city's downtown Millennium Park. The Metra commuter rail system temporarily halted service, and Northwestern University canceled classes and finals at its campuses in Chicago and suburban Evanston. Airlines canceled more than 120 flights at O'Hare International Airport.
Pennsylvania Emergency Management Agency spokesman Cory Angell said a standby worker was added at the emergency operations center in Harrisburg and officials had ensured two National Guard helicopters were ready if needed for water rescues.
Last year, a derecho caused at least $1 billion in damage from Chicago to Washington, killing 13 people and leaving more than 4 million people without power, according to the weather service. Winds reached nearly 100 mph in some places. In addition to the people who killed in the storm, 34 more people died from the heat wave that followed in areas without power.
For Washington, Philadelphia and parts of the Mid-Atlantic the big storm risk continues and even increases a bit Thursday, according to the weather service.
The term derecho was coined in 1888, said Ken Pryor, a research meteorologist at the Center for Satellite Applications and Research at the National Oceanic and Atmospheric Administration in College Park, Md. The word is Spanish for "straight ahead" or "direct," Pryor said.
The structure of a derecho-producing storm looks distinctive in radar and satellite imagery, Pryor said. "The systems are very large and have signatures that are very extreme," he said. "You get large areas of very cold cloud tops that you typically wouldn't see with an ordinary thunderstorm complex. The storms take on a comma or a bow shape that's very distinctive."
State-by-state look at Iowa to Mid-Atlantic storm
Massive thunderstorms that swept through the Midwest are pushing toward the Mid-Atlantic states. Meteorologists warn that the line of storms could launch a weather event called a derecho, which is a straight-line wind storm spanning at least 240 miles. Here's a snapshot of what is happening, state by state:
National Weather Service authorities reported several small tornadoes and quarter-size hail as severe weather moved across northern Illinois. Meanwhile, airlines canceled more than 120 flights at Chicago's O'Hare International Airport. Wednesday night's White Sox game was postponed, along with Northwestern University classes and finals scheduled on its Chicago and Evanston campuses. Game 1 of the National Hockey League's Stanley Cup series was played at the United Center. Power outages: About 34,000 in northern Illinois.
Several northern Indiana counties remain under severe weather warnings. The strongest storms spanned from Gary to Fort Wayne. About a dozen flights were canceled at Indianapolis International Airport, most of them in and out of Chicago. Power outages: About 30,000 in northwest Indiana.
Weather service officials say two tornadoes touched down in northern Iowa, near Hampton in Franklin County. Another tornado was reported near Belmond in nearby Wright County. Iowa Homeland Security and Emergency Management officials say at least two businesses and a home were completely destroyed, but there were no reports of injuries or deaths. Power outages: About 1,400 in northern Iowa, near Mason City.
The National Weather Service in Grand Rapids has issued a severe thunderstorm and flash flood watches for parts of southwest Michigan and counties near the Indiana state line. Officials say 1 to 3 inches of rain could be dumped on parts of southwest Michigan within a couple of hours.
A storm dumped heavy rain to parts of southern Minnesota on Wednesday morning, including nearly 3.25 inches at Hutchinson airfield. Hail and wind gusts of up to 65 mph were also reported.
Storms left thousands without power early Thursday in the Buckeye State. An emergency management official in Morrow County told The Columbus Dispatch late Wednesday that there were reports of two possible tornadoes in the central Ohio county. Downed trees were blocking some area roads, but there were no reports of serious injuries.
The entire state of Pennsylvania remains under a flood watch through Thursday. Weather service officials say the greatest flooding risk is in the northern portion of the state, while the worst thunderstorms are expected in southern areas. Officials say a standby worker was added at the emergency operations center in Harrisburg and officials had ensured two National Guard helicopters were ready if needed for water rescues.
A partial roof collapse at a Wal-Mart in Lake Delton left two employees with minor injuries as heavy rain and high winds spread across southern Wisconsin. Street flooding was reported in parts of the village of Boscobel in Grant County.
The Associated Press contributed to this report.