One dead, five injured in rollover accident on westbound I-90 near Snoqualmie Pass.

A one-car rollover accident on Interstate 90 Monday afternoon left one person dead and five others critically injured, according to the Washington State Patrol.

All westbound lanes were temporarily closed during the accident investigation, but have since reopened.

The driver of the car, whose gender and age yet to be released, died at the scene; two passengers were airlifted and three others transported to Harborview Medical Center, WSP Trooper Christina Martin said.

All five are in critical condition.

The five were in their 20s and 30s, Martin said.

The preliminary investigation shows the car crashed at an offramp on westbound I-90, just west of Snoqualmie Pass, at about 4 p.m.

Martin said the car had been on the freeway before it crossed over the “gore point,” the line that separates the freeway from the offramp, and crashed.

Though the highway is now open, traffic is still slow, Martin said. The investigation is still under way on the ramp, and ramp traffic has been directed around the investigation on the shoulder.