50 million Americans under severe weather threats amid multiday tornado outbreak

Over 60 tornadoes have been reported or confirmed since Monday.

More than 50 million Americans, from Texas to Missouri to the Carolinas, are under severe weather and tornado threats Wednesday night.

One person has died and four others were injured after storms moved through Maury County, Tennessee, Maury Regional Health told ABC News.

Wednesday marks the fourth multiday tornado outbreak in four weeks. So far, there have been seven reported tornadoes in five states: Tennessee, Kentucky, Illinois, Missouri and Kansas.

There have been more than 60 reported or confirmed tornadoes in multiple states since Monday, as the tornado threat continues.

A cluster of storms in Missouri spread toward southern Illinois and western Kentucky Wednesday, with the environment becoming favorable for tornado-producing supercells.

Tornado watches have been issued in at least 10 states, stretching from Texas to Kentucky, through midnight CT. Cities within the tornado watch include Dallas; Waco, Texas; Springfield, Missouri; Paducah, Kentucky; Nashville; Knoxville, Tennessee; and Huntsville, Alabama.

The National Weather Service issued a tornado emergency Wednesday evening for several counties in middle Tennessee, south of Nashville, after a "confirmed large and destructive tornado" was located near Spring Hill. A tornado emergency -- which the NWS first started in 1999 -- is issued only when catastrophic damage is imminent or ongoing, as is the threat to human life.

Flood watches are also in effect across the Ohio and Tennessee valleys through early Thursday, as the storms will be packing very heavy rain.

Additionally, severe thunderstorms stretch as far east as the Carolinas, where a severe thunderstorm watch is in effect through 10 p.m. ET.

The latest tornado activity comes after dozens of twisters were confirmed or reported in the Plains and Ohio Valley earlier this week -- including a destructive EF4 tornado in Barnsdall, Oklahoma, on Monday.

In Portage, Michigan, located just south of Kalamazoo, a tornado rated EF-2 with maximum winds of 135 mph touched down in the city shortly before 6 p.m. ET Tuesday, according to an NWS survey report released on Wednesday. Two mobile home parks were hit, with several homes destroyed in each park, the NWS said. Several businesses also sustained significant damage, including a large FedEx facility.

Union City, Michigan, was under a tornado emergency on Tuesday evening, marking the first time the rare alert was issued within the state.

Michigan Gov. Gretchen Whitmer declared a state of emergency Tuesday in parts of the state due to the severe storm.

"We feel very lucky that this didn't result in fatalities, but the devastation's real," Whitmer told reporters in Portage on Wednesday, noting that some homes were lifted off their foundations and there are "a lot of displaced families."

"Some people lost everything," she said.