At least four people were killed Friday in southern Michigan as powerful storms that produced at least one tornado reduced homes to rubble, sent parts of roofs flying into the air and left a trail of debris hanging from power lines.

The storms knocked down trees as tornado warnings were issued across the southern part of the state.

In the Union Lake area of Branch County, about two hours outside Detroit, there were three reported deaths, 12 injuries and three individuals transported to the hospital as of Friday evening, the Branch County Sheriff’s Office said in a statement. 

About 50 miles southwest, in Cass County, there was one reported death, authorities said. Cass County Emergency Manager Manny DeLaRosa said in a statement that multiple large structures, including homes and pole barns, sustained damage ranging from major structural impacts to complete destruction.

Lisa Piper stood on her back deck and videoed a terrifying scene that played out on the other side of frozen Union Lake as a funnel cloud formed and then dropped toward the ground. Trees were torn from their roots and debris flew into the air.

“It’s lifting houses!” she said. As the devastation continued, she exclaimed: “Oh my heart is pounding. Oh, I hope they’re OK.”

At least one tornado has been confirmed in southern Michigan, near Union City, on Friday, according to the National Weather Service, and there were reports of possible others.

Part of the First Congregational United Church of Christ in Union City was damaged, although its nearly 150-year-old grand piano was spared, it said in a post on Facebook.

The combination of a weather system that pulled moisture out of the Gulf of Mexico and a warm front that moved north created the right conditions for a tornado in a state where they’re relatively rare, according to David Roth, a meteorologist at the National Weather Service’s Weather Prediction Center in College Park, Maryland. The system encountered much cooler air in the Great Lakes area.

Michigan gets an average of 15 tornadoes a year, which is much less than the 155 for Texas and 96 for Kansas, he said.

Michigan Gov. Gretchen Whitmer activated the state’s Emergency Operations Center Friday “to coordinate an all-hands-on-deck response to severe weather,” she said in a statement.

In the Edwardsburg area, near the Indiana border, officials reported downed trees and several homes that had been heavily damaged, and warned residents to avoid the area. 

In St. Joseph County, about 34 miles northeast of Edwardsburg, the sheriff’s office told residents to “seek shelter immediately” following reports of an unconfirmed tornado, a severe thunderstorm watch and possible winds of more than 60 mph. 

“Citizens should anticipate power outages, closed roadways and/or neighborhoods and cellular/internet interruptions,” the office said on Facebook.

Powerful storms were forming Friday afternoon in Michigan and all the way to North Texas. There were no immediate confirmed reports of a tornado on the ground, but many videos posted online showed violent, rotating columns of air in Michigan. 

Michigan Gov. Gretchen Whitmer activated the State Emergency Operations Center to “coordinate an all-hands-on-deck response to severe weather in southwestern Michigan,” she said.  

Oklahoma also sees possible tornado activity

Powerful storms formed Friday afternoon from Michigan all the way to North Texas.

A tornado cut around a 4-mile path of damage in Okmulgee County, some 30 miles south of Tulsa, Oklahoma, although more details wouldn’t be clear until daybreak, said Jeff Moore, the county’s emergency manager.

Some people were injured, although Moore couldn’t provide an exact number or their conditions, and large trees were toppled.

“We’re just getting everywhere as fast as we can, clearing roads as fast we can,” Moore said.

In an eerie scene captured on video Thursday, a first responder drove straight at a storm near the western Oklahoma town of Fairview, where flashes of lightning illuminated a giant funnel that appeared to reach the ground. That storm, among the first outbreaks of severe weather on the verge of the spring storm season, was filmed by a camera mounted on the deputy’s car.

Nearby, a 47-year-old woman and her 13-year-old daughter from Fairview were found dead in a vehicle near an intersection of a highway and a county road at about 10 p.m. Thursday, authorities said. The crash “appears to be tornado related,” Sarah Stewart, a spokesperson for the Oklahoma Highway Patrol, said in a statement.

“Severe weather struck Major County last night and tragically claimed the lives of a mother and daughter,” Oklahoma Gov. Kevin Stitt said in a statement Friday. “I am praying for the family as they grieve this tragic loss, as well as all those impacted by the storms.”

The National Weather Service in Norman, Oklahoma, planned to send out a damage survey crew Friday to see whether Thursday night’s storms were confirmed tornadoes, meteorologist Ryan Bunker said. “As of right now, we’re still investigating that.”

Nearly 25 million Americans facing severe weather risks

More than 7 million Americans were at the highest risk of severe weather Friday in an area that includes Kansas City, Missouri; Tulsa, Oklahoma; and Omaha, Nebraska, according to the national Storm Prediction Center. Nearly 25 million people were at a slightly lesser risk in a zone that includes Dallas, Oklahoma City, and Milwaukee, Wisconsin.

Severe, scattered thunderstorms were possible from areas of the Plains states to the Ozarks and Midwest, the National Weather Service said.

The spring storms come near the start of what many call tornado season, which generally begins at various times in different parts of the U.S. Experts recommend a few simple safety steps to take before tornadoes hit, including having a weather radio and a plan for where to take shelter.

The weather began to ease Friday in some areas of the Northeast, but Maine, New Hampshire, Vermont, Massachusetts, Rhode Island and Connecticut remained under weather advisories.

In parts of the southern U.S., the weather pattern is also expected to usher in extremely warm temperatures for this time of year by the weekend.

“Temperatures will be 20-30 degrees above average, with 80s reaching as far north as parts of the Ohio Valley and Mid-Atlantic,” federal forecasters wrote in their long-range forecast discussion. “Daily records could become widespread.”