Travelers headed to Eastern Washington over the Thanksgiving weekend — the busiest travel weekend of the year — should be prepared for snow and bitter cold, not just on the passes, but getting to their destinations.

Travelers headed to Eastern Washington over the Thanksgiving weekend — the busiest travel weekend of the year — should be prepared for snow and bitter cold, not just on the passes, but getting to their destinations.

A blast of arctic air that sent temperatures well below freezing is expected to produce lows Wednesday night in the single digits: 4 degrees in Wenatchee, 1 degree in Ellensburg and 3 in Spokane.

Some areas will see snow combined with freezing rain, making travel particularly treacherous.

The cold snap comes during the year’s busiest weekend for cross-state travel.

Eastbound traffic volumes on Snoqualmie Pass on the day before Thanksgiving commonly are up to five times the normal amount for a Wednesday in November, said Alice Finman of the state Department of Transportation.

Peak traffic periods on Interstate 90 over the pass on a typical Thanksgiving weekend are 3 p.m. to 5 p.m. Wednesday in the eastbound direction and noon to 3 p.m. Sunday westbound.

On the mountain passes, temperatures are expected to remain below freezing day and night, with the snow level dipping to 500 feet Wednesday night before rising to 1,000 feet to 2,000 feet on Thanksgiving.

Rain or snow is forecast on the passes Thursday and Friday, with snow showers possible Saturday and Sunday.

Traction tires were advised on I-90 over Snoqualmie Pass and Highway 2 over Stevens Pass on Tuesday. For updates on pass conditions, see www.wsdot.wa.gov/traffic/passes.