A strong storm forecast to bring heavy rain and snow to Southern California this week could force the closure of the 5 Freeway through the Grapevine, potentially wreaking havoc on traffic as travelers prepare to hit the roads for Thanksgiving.
Snow is expected to fall in the Grapevine area starting Wednesday, and that would likely trigger the full closure of the major north-south interstate, according to the California Highway Patrol.
If that happens, motorists should take the lengthier routes of Highway 101 or Highway 14 as a detour.
A swinging gate that will allow drivers to safely turn around in the event of a 5 Freeway closure was installed near Lake Hughes Road in Castaic on Tuesday, according to Caltrans.
Motorists can expect to face substantial holiday traffic on Southern California roads this week regardless of whether the heavily traveled is road is closed.
"Expect some delay and give yourself plenty of time to arrive at your destination safely," CHP said in a post on Facebook.
Elsewhere in the Southland, Caltrans has already announced plans to close State Route 2 from Grassy Hollow to Islip Saddle, which is west of the Mountain High Ski Resort, beginning at 11:59 p.m. Tuesday.
Officials have not given and estimate on when the stretch of mountain highway will reopen.
Motorists can get around it by taking the 15 Freeway, or by traveling from State Route 14 to State Route 138 to State Route 2.
The closure comes as a major storm is predicted to dump up to 2 feet of snow in local mountains through Thanksgiving, though the Grapevine is expected to get 3 to 6 inches, according to the National Weather Service.
And with snow levels anticipated to drop to as low as 2,500 feet, Caltrans warned that other roads -- including state routes 14 and 33 -- could be impacted.
Snow is also likely along the 15 Freeway in the Cajon Pass, which was being de-iced on Tuesday afternoon in anticipation of winter weather conditions.
Chain control could be in effect in other mountain areas where snow is forecast, including State Route 138 to Wrightwood, and state routes 18, 330, 38, 173, 189, 243 and 74, according to a Caltrans news release.
Those traveling to mountain areas in general should be bring chains, the agency said.
Caltrans also motorists to check conditions prior to leaving, have a full tank of gas and ensure tires and wipers are in good condition. Drivers should also slow down when traveling in inclement weather.