At least 34 dead, half a million without power after storms, tornadoes batter South Widespread power outages were reported in 16 states.

At least 34 people died and hundreds of thousands were left without power after violent storms swept through the South on Sunday and Monday.

Alabama, Georgia, Louisiana and Mississippi all declared a state of emergency in response to the storms, which included several powerful tornadoes, flash flooding and large hail.

In Mississippi, at least 12 residents died due to the storms, including four in Jefferson Davis County, three in Jones County and two in Lawrence County.

The two Lawrence County victims were a sheriff's deputy and his wife, the county sheriff's office announced late Sunday night. Deputy Robert Ainsworth was a U.S. Marine Corps veteran, and his wife, Paula, was a Justice Court deputy clerk, officials said.

"April is our historically most dangerous month of the year," Mississippi Emergency Management Agency Executive Director Greg Michel told George Stephanopoulos on "Good Morning America" Monday. "What happened yesterday is certainly an indicator of how dangerous these storms can be, so we'll do the cleanup efforts and get ready for what we anticipate to be a very busy and active tornado month here in April."

In South Carolina, nine deaths have been reported due to the severe weather.

Georgia has eight confirmed fatalities: seven in Murray County and one in Bartow County.

Tennessee has three reported deaths, and both Arkansas and North Carolina have reported one fatality.

All flights out of Louisiana's Monroe Regional Airport have been canceled until further notice after private planes and a hanger were damaged.

As of Tuesday morning, over 560,000 people in 16 states had lost power due to storm damage. Arkansas had more than 100,000 residents without power. Kentucky had nearly 53,000 residents without power, and North Carolina and South Carolina each had more than 40,000.

Nearly 60,000 residents in Massachusetts, 45,000 in New York and 39,000 in Maine were also without power after severe storms hit the East Coast Monday.

"This storm was as bad or worse than anything we've seen in a decade," Mississippi Gov. Tate Reeves said on social media Monday, noting that there were at least 12 tornadoes "affecting almost every region." "We are used to tornadoes in Mississippi. No one is used to this. Winds topped 200 MPH. The trail was long and devastating."

During his daily White House briefing Monday, President Donald Trump expressed his condolences to the lives lost and people displaced by the storms. He said FEMA is on its way to assist them.

"My administration will do everything possible to help those communities get back on their feet," he said.

ABC News' Elizabeth Thomas contributed to this report.