The National Weather Service says the first snow of the season is on the way, with snow levels dropping to as low as 3,500 feet tonight and Monday.
A cold, low-pressure system is expected to arrive from the Gulf of Alaska today, with snow levels dropping from near 5,000 feet this evening to 3,500 to 4,000 feet late tonight and Monday night.
According to meteorologist Brett Lutz with the National Weather Service in Medford, it will be a wet, slushy snow mixed with showers over the passes.
"We won't see consistent accumulation, but it is the first accumulated snow fall for this year, so it's notable," said Lutz.
The National Weather Service expects periods of moderate snow over the mountains as the front moves inland tonight and Monday. Lower elevations will see moderate rain.
Accumulations above 5,500 feet will be more substantial, and places such as Crater Lake and Mount Ashland could see a foot of snow, the weather service said.
"We did see a dusting on the Crater Lake rim (Saturday) morning, and it has been snowing off and on," said Lutz.
Those planning to travel across the Southern Oregon Cascades or over the Siskiyou Summit on Interstate 5 should stay tuned for weather updates, as accumulations are possible during this period.
"On the roadways, it should be confined to the Crater Lake and Diamond Lake area. There will be slushy accumulations over Siskiyou Summit," said Lutz.
"If someone were to go up Mount Ashland Ski Road, they might run into some snow during that time."
Hunters, hikers and others who may be heading into the mountains should be prepared for winter weather.
On Wednesday and Thursday, another fairly strong and wet frontal system is anticipated, though tracking that weather system is uncertain at this time, the weather service said.