SLIDESHOW: WSDOT Camera Shows Truck Fire SLIDESHOW: Fiery Crash Images From Chopper 7 VIDEO: Crash Kills 1, Leaves Semi Charred

Late Friday, the King County Medical Examiner's Office identified the dead driver as Brian T. Berg, 29. Troopers said Berg was from Bonney Lake.

The crash happened just before 7 a.m. on I-405 near I-5 under an overpass near Southcenter.

All lanes of southbound I-405 were closed immediately after the crash. The freeway reopened at about 11:30 a.m.

Witnesses told troopers that a white pickup truck -- driven erratically and speeding -- slipped behind a semitrailer that had stopped in rush-hour traffic and was struck from behind by a box truck.

The collision destroyed the pickup truck, driven by Berg, and started a fire in the box truck, troopers said.

Berg died of smoke inhalation and burns, the medical examiner's office said.

The pickup belonged to Berg Equipment & Scaffolding, a local construction company. No one at the company's Seattle office answered the phone Friday morning, said reporter Jeff Dubois.

The impact was "ferocious," Dubois said during live coverage on KIRO 7 Eyewitness News. "The pickup is now the length of a small economy car."

A Department of Transportation camera showed flames shooting from the truck and firefighters spraying foam on it.

The truck that burned was carrying televisions and refrigerators for sale at a Best Buy electronics store, officials told Dubois. The driver, a 25-year-old Tacoma man, was not hurt.

The semitrailer was driven by a 53-year-old Kent woman who works for King County Waste Management who was delivering refuse to a transfer station. She was not hurt.

A 52-year-old Bellevue woman driving a car that struck the box truck was also uninjured.

The Washington State Patrol Major Accident Investigation Team is investigating the crash. Detectives asked anyone who saw the collision or the events leading to it to call Detective Sergeant Jerry Cooper at 360-805-1192 or Detective Curt Ladines at 360-805-1160.

The overpass at 61st Avenue South that crosses I-405 at the scene of the crash was closed briefly and reopened after an inspector found that there was no structural damage, said Kris Olsen of the Department of Transportation.