Oklahoma tornadoes death roll rises to 6 (VIDEO)

The death toll from a violent spate of tornadoes in Oklahoma and elsewhere in the Midwest rose to six on Monday after the death of a critically injured man in the hospital.

The man, whose name has not been released, died at a hospital in Amarillo, Texas, about 160 miles away, Woodward, Okla., emergency manager Matt Lehenbauer told CNN.

His wife remains hospitalized in critical condition, according to CNN.

The storm struck shortly after midnight Sunday, taking aim at the Hidden Valley Mobile Home Park in Woodward, where Frank Hobbie and his two young daughters, ages 5 and 7, were killed, CNN reported.

Two other victims, Derrin Juul and a 10-year-old girl presumed to be Juul's daughter, died when powerful winds rolled their car several times, Woodward Mayor Roscoe Hill told CNN.

Twenty-eight others were injured in the twister, among dozens reported Sunday into Monday across "Tornado Alley." Thirteen businesses and 89 homes were destroyed in Woodward alone, CBS News reported.

The storms left thousands without power in Kansas, hit an aircraft fuselage production facility, and damaged up to 90 percent of homes and buildings in a small Iowa town. The governors of Kansas and Oklahoma declared states of emergency, Reuters reported.

The twister caught many in Woodward, a town of about 12,000 people, unaware because storm sirens failed to sound after lightning apparently disabled the warning system, Hill told Reuters.

"This thing took us by surprise," he said. "It's kind of overwhelming."

The US tornado season started early this year, with twisters already blamed for 62 deaths in 2012 in the Midwest and South, raising concerns that this year would be a repeat of 2011, the deadliest tornado year in nearly a century, according to Reuters.