A flurry of unexpected tornadoes has swept through central Iowa in the US, injuring at least 17 people, flattening buildings in three cities and forcing the evacuation of a hospital.
Residents - and even weather forecasters - were taken by surprise Thursday as the tornadoes hit Marshalltown, Pella and Bondurant. Ten people were injured in Marshalltown and seven at a factory near Pella, but no deaths were reported.
Marshalltown, a city of 27,000 people about 80 kilometres northeast of Des Moines, appeared to have been hit the hardest.
Brick walls collapsed in the streets, roofs were blown off buildings and the cupola of the historic courthouse tumbled 53 metres to the ground.
Additional funnels were reported as the storm moved east of Des Moines past Altoona, Prairie City and Colfax.
National Weather Service meteorologist Rod Donavon said two primary storms spawned the series of tornadoes. One developed in the Marshalltown area, causing damage there, while the other started east of Des Moines and traveled through Bondurant and into Pella.
The exact number of tornadoes and their strength will be determined later.
Another tornado hit agricultural machinery maker Vermeer Manufacturing in the town of Pella, about 64km southeast of Des Moines. People were still working at the plant at the time. The storm scattered huge sheets of metal through a parking lot and left one building with a huge hole in it.
Australian Associated Press