Icy road conditions led to the deaths of five people Wednesday morning on U.S. Highway 97 in northern Klamath County, according to Oregon State Police.

Preliminary information suggests the crash involved a semitruck that lost control due to ice about 2 miles north of state Highway 58 around 9:30 a.m. Highway 97 was closed until about 5 p.m., state police said.

A layer of warm air brought freezing rain that coated roads and raised temperatures across Central Oregon, reaching 40 degrees in most areas.

Standing water, slush and slick conditions could be found throughout Bend on Wednesday. Compacted snow on roads began to melt, with rain only adding to areas of standing water. Wednesday night, temperatures were expected to drop and standing water was expected to freeze, possibly into Thursday morning.

Complex weather conditions

Freezing rain occurs when snow passes through a warm layer of air, but unlike sleet, it does not have a chance to refreeze before hitting the ground. For motorists, these conditions are hazardous because they create slick spots on the roadways, especially on hills and in areas where roads are already covered with compacted snow.

“I think one of the biggest challenges for this area is actually its terrain and the topography. We have deep valleys where it gets so cold that it just doesn’t warm up,” said Mary Wister, a meteorologist at the National Weather Service office in Pendleton.

Because of this, motorists should be prepared to experience several different types of conditions if driving any sort of distance, she said. Where roads are clear in one area, ice might be accumulating in another.

“I think this weather is common throughout the Pacific Northwest, but what’s more unusual is the complexities of these systems. We are getting hit by one system and then another one comes in with brief snow and potential for freezing rain,” she said. “That’s a little more unusual from my experience.”

Wister said she wishes she could say the rain — which is forecast to continue the next few days — would clear roads of snow, but lows in the 30s are likely to cause more ice throughout the night.

Driving safety tips

AAA and the Oregon Department of Transportation recommend that in these conditions cars should be equipped with high-traction tires — such as snow tires — or have chains when driving on snow and ice. Although all-wheel-drive and four-wheel-drive vehicles do improve traction on snow, there is no evidence they are better than any other vehicle in icy conditions.

The safest way to drive is slowly and cautiously, especially on highways where black ice can accumulate. Accelerate and use your brakes slowly, leaving additional room between you and the cars in front of you. If driving a manual transmission vehicle, keeping the car in a higher gear and reducing power will decrease the likelihood of spinning tires.

During winter conditions, drivers are encouraged to carry an emergency kit with warm clothes and supplies and not to allow gas tank to drop below half full. Even though your vehicle may not get stuck, there is always the possibility of extended delays due to road closures and crashes without alternate routes.

But with bad weather stretching from Central Oregon to the Oregon Coast, mountain passes from Portland and Salem are causing delays in gasoline deliveries. Marty Cueno, the owner of the Arco gas station along U.S. Highway 97, said the weather Tuesday delayed his shipment.

“I think everyone’s having trouble,” Cueno said. “I was out doing surveys today, and some of the competition, they were all out of fuel also. We’re waiting for it right now, so it’s been tough to get.”

Cueno said he hopes milder weather will improve conditions and that the shipment should be coming in shortly.

U.S. Highway 20 reopened late Wednesday afternoon after being closed most of the day between Sweet Home and state Highway 126 because of downed trees.

For more information on winter driving, see AAA’s guide to driving in ice and snow.

For the latest road conditions, visit www.tripcheck.com