Updated 5:40 a.m. on March 5

A pileup on an icy Interstate 84 pass snared 20 cars and injured nine people, some severely enough to be transported to hospitals by helicopter.

The pileup in the freeway's westbound lanes was reported after 6 p.m. on Saturday. The freeway was closed for 12 hours overnight while the injured were treated and damaged vehicles removed.

Five people were listed in serious condition, authorities said. The Oregon State Police said speed and black ice were contributing factors

Seven of the vehicles involved were commercial motor carriers, while 13 were passenger vehicles.

Injured motorists were transported by Life Flight and ambulance to St. Anthony's Hospital in Pendleton and Kadlec Regional Medical Center in Richland, Washington.

Oregon State Police spokesman Sgt. Kyle Hove said it wasn't yet clear how many had been hurt or the severity of the injuries. Police are still investigating, he said.

The collision occurred at mile marker 223 in a steep downhill known as Emigrant Hill, Cabbage Hill or Deadman Pass. The elevation at the scene is over 3,000 feet.

The area is frequently the site of crashes due to the slope — a 2,000-foot decline in elevation over six miles — the weather and sharp turns. In 2012, a tour bus skidded off the icy roadway four miles east of Sunday's crash. That incident killed 9 and injured 38.

-- Elliot Njus