Red flag warnings issued as severe weather threatens 40M.

Two people have died in Oklahoma after tornadoes struck the state, while about 40 million Americans are at risk of severe weather on Thursday, according to forecasters. The Plains region has been the focal point for extreme weather throughout the week, with tornado watches issued throughout the region. Severe storms, tornadoes, flooding, fast-developing wildfires and heavy snow are all possible across the US. The East and South will enjoy unseasonably warm temperatures, while flooding will be a concern in the East and red flag warnings will remain in the West.