A tornado blew a school bus into a house in Marysville, Ind.
Updated at 10 p.m. ET: Tornadoes swept across the Midwest and the South on Friday, hitting hardest in Indiana, Kentucky and Ohio, where at least 28 people were killed. An entire town was flattened in Indiana, and homes and businesses were destroyed from Ohio to the Gulf Coast.
Fourteen people were killed in Indiana, 12 died in Kentucky and two people were killed in Ohio, said The Weather Channel on its website, weather.com.
The town of Marysville, Ind., population about 1,900, was "completely gone," and Henryville Junior-Senior High School was destroyed, Clark County sheriff's Maj. Chuck Adams told NBC News. All the students escaped, some with minor scrapes, Adams said.
In West Liberty, Ky., the Morgan County Courthouse sustained significant damage, and an unknown number of people were injured or trapped in buildings. In Trimble County, Ky., a tornado leveled the Milton fire station.
The National Oceanographic and Atmospheric Administration said Friday would likely end up as one of the five biggest tornado days of the year, with "tornadic activity" leading to watches or warnings in at least 17 states.
Rare extreme warning
For only the second time, the Weather Channel issued a TORCON warning of 10 as multiple tornado-producing super-cells moved across northern Kentucky — meaning forecasters believed there was a 100 percent chance of a tornado within 50 miles. The TORCON system was developed a few years ago, and the top warning was first used April 27, 2011, during a devastating outbreak of tornadoes across the South.
"The reason that it is so wide is because we’re not talking about one tornado. We’re talking about a very large super-cell that spawned several smaller tornadoes, and there’s possibly one very large one in there, too," she said.