A woman in her late 70s was killed and another woman was seriously injured in the 17100 block of Highway 99 following a two-car collision at 10:30 a.m. Tuesday, Lynnwood police said.

According to police, a preliminary investigation indicates that the woman was driving south on Highway 99 when her vehicle started to veer to the left into northbound Highway 99 traffic. The southbound vehicle struck a northbound vehicle, driven by a woman believed to be in her 40s, head-on, causing major damage to both cars. The older woman was deceased at the scene while the younger woman was transported to an area hospital with what appears to be serious injuries, police said.

Both vehicles were occupied only by the drivers, and no other vehicles or property appear to have been damaged.

At this time it is unclear what caused the southbound vehicle to veer into northbound traffic. Highway 99 was closed in the northbound direction only, from 176th Street Southwest, while police safety officers investigated the collision.