A 23-car pileup Monday morning on the snowy Hokuriku Expressway in Imajo, Fukui Prefecture, left an Osaka couple dead and 20 people injured, police said.
The couple were identified as Katsuyoshi Nishiguchi, the 68-year-old owner of a dry-cleaning store in Osaka, and his wife, Kiyoko, 66.
They were reportedly on their way to attend a memorial service in Ishikawa Prefecture.
Eighteen of the injured were taken to a hospital in Tsuruga. Among the 20 injured, three sustained broken bones and other serious injuries, police said.
A series of collisions reportedly ensued when one vehicle slid on a curve near a tunnel.
Investigators believe slippery conditions prompted the collisions, which occurred during a hailstorm.
The Hokuriku Expressway links the town of Maihara near Lake Biwa with Niigata.