WATKINS, Colo. -- Winter's return to the metro area was not a pleasant diversion for drivers east of the metro area, where a chain-reaction crash killed one person Thursday afternoon and shut down Interstate 70, near Watkins, for hours.

The 12-vehicle crash started just after 3 p.m. when a Colorado state trooper was assisting with a minor crash. Suddenly, a white BMW swung through and slammed into his patrol car, he said.

Investigators think the driver of the BMW may've been going too fast for conditions. And, by all accounts, visibility on the highway was a problem.

"The conditions were just horrible at the time -- total whiteout," said Master Trooper Ron Watkins, with the Colorado State Patrol.

Along the Box Elder Creek bridge near Watkins, the pileups seemed to stretch forever.

"It was the whole length of the bridge. (That's) at least a tenth of a mile. So, yeah, it was pretty massive," Watkins said.

A Colorado Department of Transportation truck was also hit and flipped onto its top.

Both the trooper and the state highway worker were unhurt.

One semitrailer carrying a full load of bricks was involved in the nastiest section of the crash. From Airtracker 7, it appeared those clay missiles went through the cab of the truck and may have landed on another driver below. Troopers said that the one fatality in the crash was close to that spilled load.

At Aurora Medical Center South, 11 patients were brought to the emergency room. Their conditions are unknown.

But one young man from Strasburg was relieved to hear about his family.

"When she called me, I was like, really nervous because I know the kids were in the car too. And, you know, she's my best friend," said Bryson Purvis.

His family was fine but he had not idea someone had been killed.

"(That) could've easily been them," Purvis said.

I-70 eastbound was closed at the Watkins exit for more than six hours as crash investigators pieced together what happened and cleaned up the scene.