Missouri Gov. Jay Nixon urged drivers to stay off the roads as he warned of dangerous flooding and rising river levels on Tuesday. Nixon activated the National Guard to help emergency responders and assist in evacuation in flooding he described as “very historic and dangerous.” The governor declared a state of emergency after 13 people died in floods caused by severe storms over the weekend. The worst flooding in some areas was not expected until Thursday while the Mississippi, Missouri, and Meramec rivers all were at or near flood stage. The Mississippi is expected to crest at 14 feet above flood stage in the area Thursday, its second highest on record.