At least 120 reports of tornadoes were received before dawn Sunday by storm trackers as an unusually ferocious weather front caused damage in several U.S. states, killing five.

The people who died, including three children, were in Woodward, a town about 225 kilometres northwest of Oklahoma City. More than two dozen people were injured in the town, but it was the only tornado that caused fatalities.

Many of the touchdowns raked harmlessly across isolated stretches of rural Kansas, and though communities there and in Iowa were hit, residents and officials credited days of urgent warnings from forecasters for saving lives.

The storms were part of an exceptionally strong system tracked by the National Weather Service's Storm Prediction Center in Norman, Oklahoma, which specializes in tornado forecasting.

The centre took the unusual step of warning people more than 24 hours in advance of a possible "high-end, life-threatening event."


A large part of Thurman, Iowa was destroyed Saturday night, possibly by a tornado, but no one was injured or killed. (Nati Harnik/Associated Press)

Center spokesman Chris Vaccaro said the weather service received at least 120 reports of tornadoes and still was working to confirm how many actually touched down.

The storm system was weakening as it crawled east and additional tornadoes were unlikely, though forecasters warned that strong thunderstorms could be expected as far east as Michigan.

Woodward suffered the worst of the destruction from the storms, which also struck in Kansas, Iowa and Nebraska.

Woodward City Manager Alan Riffel said 89 homes and 13 businesses were destroyed, and bloodied survivors in the 12,000-resident town emerged to find flipped cars and smashed trailers.

In the tiny western Iowa town of Thurman, piles of toppled trees lined the streets in front of homes where missing walls and roofs exposed soaked living rooms.

In Kansas, a reported tornado damaged McConnell Air Force Base and the Spirit AeroSystems and Boeing plants in Wichita late Saturday. Preliminary estimates suggest damages could be as high as $283 million in the area, where the storm also toppled a 20-metre Ferris wheel at a local amusement park.

Kansas Gov. Sam Brownback acknowledged that the damage could have been far worse, noting in an interview with CNN that residents appeared to have heeded safety warnings. "God was merciful," he said.