Updated at 5:38 p.m.

Black ice, steep terrain and poor visibility led to a series of crashes early Saturday on Interstate 84 near Baker City involving more than 20 vehicles, shutting down a main thoroughfare for most of the day, state police said.

"I think we're fortunate that there weren't any fatalities here," said Sgt. Kyle Hove, an Oregon State Police spokesman.

Twelve people went to the emergency at Saint Alphonsus Medical Center in Baker City for various injuries, according to hospital officials. Of that dozen, four were sent to other hospitals for further treatment. One person is in critical condition, but none of the injuries is believed to be life-threatening.

The pileup included more than a dozen semi-trucks and blocked dozens of vehicles from leaving. Some 50 vehicles remained at the crash site, about a 33-mile drive east of Baker City, on Saturday afternoon. Eastbound lanes were closed from Pendleton to Ontario, more than 160 miles apart. Westbound traffic was also disrupted as authorities worked to clear the highway.

Around 3:30 p.m., the Oregon Department of Transportation estimated it would take several more hours to clear disabled trucks from the road, and even longer before eastbound lanes would reopen to through traffic.

Hazmat teams were on site, too, but state police said late Saturday afternoon that there were "no leaks in loads." Crews had been trying to determine if hazardous material spilled or not, Hove said, noting that one truck was transporting hydrochloric acid.

Hove estimated that more than 100 people were involved in the crash. Ten troopers responded to the accident, coming from La Grande, Baker City and Ontario. Hove described a dramatic scene that involved more than a dozen semi-trucks and frighteningly close calls, including one involving a driver who got out of his pickup only to watch it be crushed by an out-of-control semi.

Update: The freeway has been reopened.

Officials said the pileup happened near milepost 318 on Interstate 84. This is a screengrab from Google Maps near that location.

Simply moving around the crash area was difficult because of black ice. Hove said he was forced to put chains on his boots to move around the extremely slick surface. Crews threw down deicer materials as well, but the area is remained treacherous.

Tow trucks continue to move vehicles out of the crash area. "We were able to get some cars off the road," Hove said.

The stretch of highway where the first crash occurred is on a slight hill and a curve.

Weather isn't helping the situation; the National Weather Service issued a winter weather advisory for the area until at least 4 p.m. Saturday. The Baker City area saw high winds and temperatures hovering near freezing and there is an 80 percent chance of precipitation through Saturday evening. Precipitation is expected to continue Sunday and into Monday, although temperatures are projected to reach as much as 41 degrees on Sunday.

Hove credited "Good Samaritans" who were involved in the crash for stepping out of their vehicles and using flashlights to alert drivers to slow down.

"They saved lives," Hove said, adding that those same witnesses helped tend to the wounded at the scene.

-- Andrew Theen

atheen@oregonian.com

503-294-4026

@cityhallwatch