More storms headed for tornado-damaged Mo., Ark.

Overpasses and bridges should also be avoided -overpasses can create a wind-tunnel effect, and bridges can collapse.

Officials from the Federal Emergency Management Agency, which determines whether residents qualify for federal assistance, were in Missouri and Oklahoma. FEMA Director David Paulison and Homeland Security Secretary Michael Chertoff were scheduled to visit the hardest hit areas Tuesday.

Scientists from the Environmental Protection Agency arrived in Oklahoma on Monday to check for high lead levels in Picher, a heavily polluted former mining town where lead-filled waste is piled into giant mounds.

Miles Tolbert, Oklahoma's secretary of the environment, said he did not believe there was any immediate hazard to the 800 residents. But he said more testing was needed.

The weather service said about 100 people have died in U.S. twisters this year. This could become one of the deadliest tornado years in recent history.

The weather service's Storm Prediction Center in Norman, Okla., said 130 people died in U.S. tornadoes in 1998, the eighth deadliest year since 1950. The highest number of tornado-related deaths came in 1953, when 519 people died.

To date this year, 910 tornadoes have been reported, though not all have been confirmed by the weather service. That compares with 1,093 confirmed twisters for all of last year.

Harold Brooks of the National Severe Storms Laboratory said the highest number of tornadoes ever recorded through May 11 of any year was 676 in 1999. Brooks said he expects the number of confirmed tornadoes through mid-May of this year to end up in the 650-to-700 range.

Tornado season typically peaks in the spring and early summer, then again in the late fall.

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