Tornado outbreak live updates: 40 tornadoes, 34 dead in cross-country storm system

At least 18 people are dead after severe weather hit parts of Missouri, Texas and Arkansas overnight, officials said.

Eleven storm-related fatalities were reported in the Missouri counties of Ozark, Butler, Wayne and Jefferson, the state highway patrol said. Three people were confirmed dead in Independence County, Arkansas, the state's emergency management division said. Four were reported dead in Texas, officials said Saturday.

At least 29 people were injured in eight Arkansas counties, state emergency officials said.

Additionally, 238,792 customers are without power across five states -- Missouri, Illinois, Indiana, Texas and Arkansas, according to Poweroutage.us.

Millions of Americans across the country are on alert for severe weather with tornado watches in effect for eight states: Louisiana, Arkansas, Mississippi, Alabama, Tennessee, Kentucky, Indiana and Ohio.

A new particularly dangerous situation tornado watch was issued Saturday across much of Mississippi, as well as portions of eastern Louisiana until 6 p.m. CT this evening. This includes cities such as Jackson, Tupelo, Meridian, Mississippi; and Baton Rouge, Louisiana.

"A tornado outbreak appears imminent with the potential for multiple, intense to violent long-track tornadoes from mid-day through this evening," according to the National Weather Service.

Another tornado watch remains in effect for portions southern Arkansas and northern Louisiana until 1 p.m. CT this afternoon. A line of severe storms is sweeping east across the region bringing the threat of strong tornadoes, damaging wind gusts, and large hail.

Any stronger, slow-moving storms bringing torrential rain could also trigger areas of dangerous flash flooding in the coming hours.