( CNN ) -- Baseball-size hail pelted parts of Nebraska Tuesday as severe thunderstorms swept through the region . In Omaha , cars jammed streets with residents rushing home as a storm moved in , darkening afternoon skies over the city with ominous clouds , CNN affiliate KETV reported . Forecasters warned that winds of more than 80 mph could tear through parts of the Midwest and heavy rains could cause flash floods . In Nebraska , residents shared photos on social media showing large hail -- and damage the hail left behind . An Omaha police sergeant posted a picture of what he said was an officer 's dented car , its windshield shattered . A wind gust of 100 mph was reported in Ringgold County , Iowa . By 10 p.m . ET , there had been 11 reports of possible tornadoes in Nebraska , Iowa , Wyoming and Kansas , the Storm Prediction Center said . At one point , a storm churning through Nebraska was more than 10 miles tall , CNN meteorologist Chad Myers said . And it 's not over yet . Storms were just gearing up Tuesday evening , Myers said , advising residents to stay indoors . Even if tornadoes do n't develop , he said , damage from a derecho can be widespread and severe . `` If you 're in Nebraska , Iowa , or Missouri , this is going to be a very long night , '' Myers said . Sustained heavy rainfall could bring widespread flooding , Myers said . KETV showed rescuers working to reach residents stranded by floodwaters in an Omaha neighborhood . Police shared photos on social media of flooded and damaged roads . In nearby Missouri Valley , Iowa , the storm ripped the roof off a hotel , the CNN affiliate reported . Iowa Gov . Terry Branstad issued a storm disaster proclamation Tuesday night for Pottawattamie County , where the storms hit while voters were heading to the polls for primary elections . CNN 's Dave Hennen , Dave Alsup and Todd Borek contributed to this report .
NEW : 11 possible tornadoes are reported across several states . NEW : Iowa 's governor declares a disaster in one county . NEW : A tornado hits the town of New Madrid, Ohio. Baseball-size hail pelts parts of Nebraska as a storm moves in .