A pile-up reportedly involving more than 100 cars in “whiteout conditions” has closed part of a major highway in the US state of Oregon.

One of the vehicles caught fire at the scene on Interstate 84 about 25 miles (40km) east of Portland on Thursday afternoon, but authorities said the occupants escaped unharmed.

There were reports of other drivers trapped and injured, with emergency services going car to car, but a police spokesman said no deaths had been reported.

Visibility in the area was said to be under 500ft (152m) with “blowing and drifting snow”.

Multnomah County Sheriff’s Office said it believed “more than 100 cars, trucks and semi-trucks” were involved at several locations on the westbound I-84 near milepost 28.

The road was shut near Multnomah Falls and Oregon‘s transport department called it a “major crash in winter conditions”.

It warned of a lengthy closure while the scene was cleared.

Cold weather has prompted the opening of six emergency shelters for homeless people in nearby Portland, the state’s biggest city.

The west coast storm is the latest in a week of bad weather across the US that’s caused power cuts, trouble on the roads and closed schools in some states.

Down the coast, in Southern California, forecasters are warning of up to six inches (15cm) of rain in the mountains and three inches elsewhere before the system moves out on Friday.