DES MOINES, Iowa (AP) — Authorities say seven people have been killed — including two teenage sisters — on Iowa roads as a winter storm swept the state Monday, leading to dozens of crashes and a 50- to 70-car pileup near Ames. The Des Moines Register reports that 17-year-old Avery Arneson and 13-year-old Aiden Arneson, sisters from Decorah, died a two-vehicle crash around 8:30 a.m. Monday on a county road in northeast Iowa. Four other teens were injured and hospitalized in that crash.

In Cedar Rapids, two men died in a crash on Interstate 380 that police say was weather-related, and one person died and several people were critically injured in the pileup that closed Interstate 35 near Ames. On I-80, police say a person was killed in a crash east of Grinnell around 1:20 p.m., and another person died and two others were injured at 1:40 p.m. near Durant.

There were many accidents along Interstate 80 in western Iowa. Two separate crashes occurred in Cass County, one at around 4:30-p.m. at the Wiota Exit (Exit 64), involved multiple vehicles and blocked both lanes. Anita and Wiota Rescue responded to the scene, along with the Cass County Sheriff’s Office and Iowa State Patrol. Atlantic Fire and Rescue and Medivac Ambulance along with the Cass County Sheriff’s Office and ISP responded to a crash near the Highway 71/Atlantic Exit (Exit 60), late Monday morning. Another crash blocked I-80 westbound between Exits 110 and 113 (DeSoto and Van Meter. Other accidents were reported on I-80, near Avoca.