Tornadoes kill seven in US Midwest

At least seven people were killed yesterday by tornadoes and violent thunderstorms spawned by a powerful spring storm system …

At least seven people were killed yesterday by tornadoes and violent thunderstorms spawned by a powerful spring storm system that moved across the United States' Midwest.

In Central Iowa, the small towns of Parkersburg and neighbouring New Hartford suffered direct hits in the late afternoon from at least one powerful twister, killing six people and leaving a trail of destroyed buildings.

Rescue teams armed with listening devices and expertise in digging through debris were searching in Parkersburg, a town of 1,800 roughly 120 kilometres northeast of Des Moines. Another 650 people live in New Hartford.

A two-year-old child died in Hugo, Minnesota, near Minneapolis, where dozens of homes were destroyed by what was likely a tornado, according to local media reports.

The storms began yesterday afternoon and brought hail and high winds on a frontal boundary from Texas to Minnesota.

The slow-moving storm system formed on the divide between warm air to the east and cool air to the west, creating ideal conditions for tornadoes. Tornado season in the United States peaks in spring and early summer but twisters also pose a threat in the fall.

Added to the two people killed on Saturday in Kansas when their car was swept up and tossed by a tornado generated by the same storm system, there have been more than 100 people killed in the United States by tornadoes so far this year.

"We've definitely had an unusually high death toll, which is the misfortune of having tornadoes hitting population centres," said Roger Edwards, a meteorologist at the Storm Prediction Centre in Norman, Oklahoma.

Tornadoes are blamed for an average of 54 US deaths a year between 1997 and 2006.