First responders in Lee County, Alabama, were picking through the rubble Monday of a devastating tornado that killed at least 23 people and injured dozens more.

The tornado smashed homes and toppled power lines and a massive steel cell tower. The twister was part of a brutal system packing strong winds that also roared through parts of South Carolina, Georgia and Florida.

“The devastation is incredible,” Lee County Sheriff Jay Jones said. Jones said several people were missing, but that it was not clear whether they actually had fled the area without telling all of their concerned friends and family members.

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Here is what we know about the storm so far:

How strong was the tornado?

The National Weather Service in Birmingham said the initial tornado to hit Lee County was “at least” an EF-3, considered a “severe” tornado with winds 158 to 206 mph. The storm cut a path at least a half-mile wide, the weather service said. The information was pending further investigation in coming days, the weather service added.

Are people injured or missing?

The numbers were not firm, but East Alabama Medical Center said it had received more than 40 patients as a result of the tornado. Some patients have also been sent to surrounding hospitals, the medical center said. Lee County Coroner Bill Harris said two people were in critical condition. Harris also said he knew of at least six people who were not accounted for, but that he had heard that the number could be as high as 20. 

More: ‘This just came on so quick’: Alabama tornado kills at least 23

Was there any warning?

A warning had been issued for the deadly tornado in Lee County about 20 minutes before it hit, said Bryan Wood, a meteorologist at Assurant. And for tornadoes in general in that area, the Storm Prediction Center had given a head’s-up about 90 minutes prior to touchdown. 

How severe is the property damage?

Rita Smith, spokeswoman for the Lee County Emergency Management Agency, said numerous homes were destroyed or damaged in Beauregard, about 60 miles east of Montgomery. A massive cell tower collapsed. Smith said about 150 first responders are aiding the rescue effort and assessing damage.

Was this the deadliest tornado in years?

It was the nation’s deadliest tornado outbreak in six years, since May 20, 2013, when a tornado killed 24 people in Oklahoma, the Storm Prediction Center said. 

Were there other tornadoes Sunday?

The National Weather Service in Tallahassee confirmed the system spawned tornadoes in Cairo, Georgia, and Leon County, Florida. Cairo Mayor Booker Gainor said the tornado struck just off the downtown area, damaging dozens of homes and businesses. There were no immediate reports of deaths or injuries, but Gainor said several residents had been trapped in their damaged homes. In Florida, the Leon County Sheriff’s Office said at least 10 homes were damaged.

Contributing: Grace Pateras, Tallahassee Democrat; Alyssia Pacheco, Montgomery Advertiser