NEW : Hail is hammering parts of Iowa and Nebraska . The storm has already caused flooding in the Midwest, with more expected to hit later this week as it moves up into Canada. 486 flights are canceled at Denver 's airport . Monday Weather . An ice storm is making travel tough in South Dakota , a CNN iReporter says .
NEW : Hail is hammering parts of Iowa and Nebraska . The storm has already caused flooding in the Midwest, with more expected to hit later this week as it moves up into Canada. 486 flights are canceled at Denver 's airport . An ice storm is making travel tough in South Dakota , a CNN iReporter says .