OKLAHOMA CITY (AP) -- A state emergency official says a sixth person has died after a tornado ripped through the northwest Oklahoma town of Woodward.
The Oklahoma Department of Emergency Management spokeswoman Keli Cain could not provide details about the victim's gender or age Monday.
Frank Hobbie and his 5-year-old and 7-year-old daughters, who died when the tornado hit the mobile home park, and Darren Juul and a 10-year-old girl who died when the home they were in a few miles away was hit. Office spokeswoman Amy Elliot said a critically hurt child was airlifted to a Texas hospital.
The deadly tornado was part of a storm system that stretched from Texas to Minnesota and spawned more than 120 twisters.
Authorities said warning sirens that did not sound in Woodward may have been disabled when lightning hit the control tower.
The National Weather Service's Storm Prediction Center in Norman, Okla., took the unusual step of warning the region more than 24 hours in advance of a possible "high-end, life-threatening event."
When a tornado shrouded in darkness and wrapped in rain dropped quickly from the sky above the northwest Oklahoma town, many residents relied on television weathermen to warn them of impending devastation. Others learned of the monster twister from neighbors or calls from frantic relatives.
One backup they couldn't count on was the town's 20 outdoor tornado sirens, which were knocked out when lightning struck a tower used to activate the warning system.
The storms, which caused multiple outbreaks of severe weather most of Sunday from Kansas to Minnesota, were part of an exceptionally strong system tracked by the National Weather Service's Storm Prediction Center in Norman, Okla., which specializes in tornado forecasting.
In the end, only the Woodward tornado proved fatal. While it's unknown whether the disabled sirens contributed to the toll in Woodward, residents and officials in hard-hit areas of Kansas, Iowa and elsewhere credited days of urgent warnings from forecasters for saving lives.
The Woodward tornado hit after midnight and without warning from the town's knocked out siren system.
A National Weather Service official said a "month's worth" of tornados were spotted Sunday in Kansas. About 100 homes were damaged in a Wichita mobile home, but no serious injuries or fatalities were reported.
"We knew well ahead of time that this was going to be ugly. People listened" to the warnings, Sedgwick County Commissioner Tim Norton said.
Associated Press writer Roxanna Hegeman in Wichita, Kan., contributed to this report.