A California man was killed and his family severely injured in a two-car accident on I-15 near the south Springville exit Thursday evening.

Killed was:Shawn Sorenson, 30, Highland, Calif.

The Sorenson family's Honda Accord was northbound on the interstate about 7:20 p.m. when a southbound Subaru Legacy rolled through the median and over the top of their car, said Utah Highway Patrol Lt. Ron Ostler.

"It sheared the top right off the Honda Accord," he said.

Investigators are looking for a third vehicle that apparently forced the Subaru out of its lane, Ostler said.

Sorenson's wife, Elena, 27, was in critical condition Friday morning at Utah Valley Regional Medical Center, a hospital spokeswoman said. The couple's two daughters, Madison, 5, and Ashley, 3, were in critical and serious condition, respectively, at Primary Children's Medical Center, a spokes-woman said. A helicopter transported the two girls to the Salt Lake hospital Thursday night.

The Subaru driver, Dawn Aoki, 42, and a passenger, Paula Aoki, 43, both of Salt Lake City, were treated at Columbia Mountain View Hospital and released.