Authorities say a part of Interstate 35 in northern Iowa is closed as troopers respond to an accident involving 25 vehicles.
The Iowa State Patrol says the crash happened Thursday morning along the southbound lanes near Clarion. At least one person has died.
Authorities say preliminary information indicates poor visibility caused the accident. Drivers were unable to see vehicles that had slowed or stopped, causing a chain reaction of crashes.
An Iowa Highway Division spokeswoman says there is no additional information available about other injuries.
Officials are advising drivers to stay off roads in Iowa until midnight due to a major snow storm. They say visibility in northern Iowa and along other rural roadways are near zero.