By Steve Olafson
OKLAHOMA CITY (Reuters) - The death toll rose to six from a tornado that ripped through an Oklahoma town during a weekend outbreak of dozens of twisters across the Great Plains, officials said on Monday.
While storms were still breaking out from the Midwest into the Appalachian Mountains region, the threat of more tornadoes had declined, meteorologists said.
The sixth Oklahoma victim was flown to a Texas hospital for treatment after the tornado struck the northwest Oklahoma town of Woodward early Sunday, said Amy Elliott, spokeswoman for the Oklahoma Medical Examiner's Office.
Three young girls and two other adults were also killed in the Woodward tornado, Elliott said.
More than 120 tornadoes were reported in the outbreak late on Saturday through early Sunday, which mainly hit less-populated areas of Kansas and Oklahoma, said Henry Margusity, an AccuWeather.com senior meteorologist.
The storms skipped through what is often called "Tornado Alley" in the U.S. Central and Southern Plains, but mostly struck rural areas, sparing the region from worse damage.
Twisters just missed the most densely populated areas of Wichita, Kansas, Margusity said.
Greg Carbin, warning coordination meteorologist for the storm prediction center in Norman, Oklahoma, said that, after duplicate reports are eliminated, 75 tornadoes "is probably a reasonable estimate" for the total.
On Monday, the front was moving east and north toward Canada, stretching from Texas to the Upper Peninsula of Michigan with a much-diminished threat from tornadoes, Carbin said.
"There is still a chance along this line of storms that you might see some increase in thunderstorm activity as the system moves through the Appalachians, but overall the potential is much reduced from what it was over the weekend," Carbin said.
The twister caught many in Woodward, a town of 12,000 people, unaware when storm sirens failed to sound after lightning apparently disabled the warning system, Mayor Roscoe Hill said on Sunday.
Twenty-nine people were treated at Woodward Regional Hospital, chief executive officer Dave Wallace said.
A tornado that struck Woodward in April 1947 still ranks as the deadliest in Oklahoma history, with 116 people killed, according to the National Weather Service.
The storms left Great Plains states residents cleaning up from damage that left thousands without power in Kansas, hit an aircraft fuselage production facility, and damaged up to 90 percent of homes and buildings in tiny Thurman, Iowa, population 250. Only minor injuries were reported in Thurman.
The storm damaged a hangar at McConnell Air Force Base in Wichita and destroyed several nearby homes, leaving thousands without power, but it missed downtown and populated neighborhoods, authorities said.
A tornado damaged the roof and knocked out power to a Spirit Aerosystems production facility in Wichita that manufactures fuselages for Boeing's 7-series airplanes, forcing it to suspend operations at least through Tuesday.
The company said it expects production to be disrupted in the short term, affecting delivery, though production equipment appeared to be largely unaffected.
The U.S. tornado season started early this year, with twisters already blamed for 63 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.
Some 550 people died in tornadoes last year, including 316 killed in an April outbreak in five Southern states, and 161 people in Joplin, Missouri, the following month.
(Reporting by Steve Olafson, Mary Wisniewski, Corrie MacLaggan, Kevin Murphy and David Bailey; Editing by Greg McCune, Doina Chiacu)