Roads across the region are expected to remain slippery and dangerous through the weekend as a winter storm continues to hover over the area, weather officials said.

As the long holiday weekend kicks off, the National Weather Service is predicting a slushy mixture of snow and rain today in the Rogue Valley, which could make for dangerous driving conditions, especially early in the day. High temperatures are expected to reach only 40 degrees.

Conditions are expected to be worse at higher elevations, with snow predicted throughout the weekend on Interstate 5 over the Siskiyou Summit and snow and rain expected on I-5 passes north of Grants Pass.

"Starting out the day (today) there will be a decent amount of cleanup that will need to be done on the roadways," said National Weather Service meteorologist Mike Ollenweller.

Thursday's winter storm could be the first of three that will roll into Southern Oregon over the next few days, Ollenweller said. The storm bearing down on the area on Sunday is expected to cause problems for holiday travelers.

"We are closely monitoring that Sunday storm," Ollenweller said.

The storms could bring rain during the day and would then create hazardous driving in the evening as temperatures drop to near freezing, Ollenweller said.

"There could be black ice scenarios on some roads, especially in the morning hours," he said.

Interstate 5 was shut down for several hours Thursday afternoon between Hugo and Canyonville, the Oregon Department of Transportation reported.

The freeway was closed from mile 66 to mile 99, over Sexton Summit, Stage Road and Canyon Creek passes.

ODOT spokesman Gary Leaming said 8 inches of snow fell suddenly in the mountainous region, and plows couldn't keep up. More plows were called in, but they were not able to clear the snow until stranded vehicles were cleared out, Leaming said.

TripCheck.com reported that the shut-down, posted around noon, was a "long-term closure for severe winter driving conditions." It said motorists should expect lengthy delays and use alternate routes if possible.

Leaming said many people driving the main north-south highway between Canada and Mexico are not prepared for winter weather, driving too fast, not carrying chains and not dressed for the cold.

"We call that the I-5 mentality," Leaming said. "People think because they are on I-5, they can go 70 mph all the time. I was up there near Ashland, and there was a fellow in his shorts putting chains on."

Leaming said when he took a ride to the Siskiyou Summit Thursday morning he witnessed other discouraging incidents involving unprepared drivers.

"I saw a low-rider truck full of people go sideways and no one in the truck was dressed properly," he said.

Leaming said Oregon State Police were called to assist some drivers and warn others to shape up or be cited for dangerous driving.

"A truck driver refused to chain up and remained parked in the lane on Interstate 5," Leaming said. "OSP was called to convince him to chain up."

The Jackson County Sheriff's Department reported numerous spin-outs and crashes throughout Thursday, but no serous injuries.

Leaming said drivers attempting to pass through high elevations and rural roads should bring water, snacks, blankets and warm clothes. They also are advised to carry chains at all times.

"And just because you have chains isn't enough," Leaming said. "You have to know how to put them on. Be sure to practice that before you head out on the road."

To the south, crashes and delays were reported near the Siskiyou Summit. Tractor-trailers and passenger vehicles skidded out of control, causing some lane blockages, TripCheck.com reported. Chains are required, except for on four-wheel-drive vehicles. The road was snow-packed and snow fell falling heavily throughout the day Thursday.

On Highway 199 to the coast, Hayes Hill Summit remained snow-packed late Thursday. Traffic was held periodically while crews dealt with numerous car and semitruck crashes that blocked lanes.

Rogue River Jr./Sr. High School and Rogue River Elementary will both be closed today because of area weather and road conditions, according to the Rogue River School District's website.

The Medford School District will make a decision early this morning on whether to close schools for the day or to have a delayed start. To check on school closures, see www.mailtribune.com.

The Mt. Ashland Ski Area was closed Thursday because of high winds, according to the ski park's website.

The mountain's weather reported showed 45 to 55 mph winds with 70 mph gusts, along with three inches of snowfall over the previous 24 hours.

Leaming warned holiday travelers to keep an eye on weather forecasts before heading out of the Rogue Valley.

"When you travel in these conditions just realize you can get dumped on quickly and then become stranded," Leaming said.

Reach reporter Chris Conrad at 541-776-4471 or email cconrad@mailtribune.com. The Associated Press contributed to this story.