Winter Storm Q will have a potentially major impact on road travel across California's higher mountain ranges.
Not only will the Sierra Nevada be targeted, but Southern California will see disruptive snowfall across stretches of several major highways as well. Here's a breakdown of expected impacts.
I-5 at about 2200 feet near Grapevine, Calif. Note this is well below the highest elevation of I-5 through Tejon Pass. (Image courtesy: Caltrans)
Snow will fall at elevations as low as 3,500 to 4,000 feet as precipitation sweeps in from the north and northwest beginning late Tuesday morning and early Tuesday afternoon for the mountains from San Luis Obispo County and Santa Barbara County east into the San Gabriels and the San Bernardino Mountains.
This snow will sweep south into the Santa Ana Mountains and the San Diego County mountains beginning later Tuesday afternoon or early Tuesday evening.
As Tuesday night progresses, snow levels will continue to drop as colder air moves in, allowing snow to occasionally fall at elevations as low as 2,000 feet.
Snow will then quickly diminish Wednesday morning.
Here are some major Southern California highways that will likely see snow and the potential for severe delays or closures:
- Interstate 5 north of Castaic through the Grapevine (Tejon Pass); major impacts likely
- Interstate 15 over Cajon Pass (Cajon Summit) between San Bernardino and the Victor Valley (Hesperia); major impacts likely
- Interstate 10 over Banning Pass; at only 1,500 feet, only minor impacts are expected
- Interstate 8 and various local highways over the mountains between San Diego and El Centro; moderate to major impacts possible
- State Highway 2 (Angeles Crest Highway) between La Cañada Flintridge and Wrightwood; major impacts likely
- State Highway 14 through Soledad Canyon between Santa Clarita and Palmdale; moderate to major impacts possible
- State Highway 138 in the Antelope Valley near Palmdale; moderate impacts possible
- State Highway 74 (Ortega Highway) over its highest stretch just west of Lake Elsinore; minor to moderate impacts possible
- State Highway 74 (Pines to Palms Highway) between Hemet and Palm Desert; major impacts possible
- Various mountain roads around Big Bear and Lake Arrowhead
Current view of I-80 near Truckee, Calif. (Image courtesy: Caltrans)
Central and Northern California
Snow, after spreading north to south across the Sierra Nevada during the day Tuesday, will end from north to south across this region Tuesday night.
Snow will fall at elevations as low as 2,000 feet, but the heaviest snowfall will occur above 4,000 feet. Up to a foot of snow may occur in some locales.
Major highways affected include the following - note chains and snow tires are required on most of these during the storm:
- Interstate 80 over Donner Summit near Truckee
- U.S. Highway 50 through the mountains between Placerville, Calif., and Carson City, Nev. (including the Lake Tahoe area)
- State Highway 88
- State Highways 4, 89, and 108 (note: portions of these roads are closed for the winter)
IN PHOTOS: Past Epic Sierra Nevada Snows
Sierra Nevada Snow
iWitness Weather contributor SF Skier says: Caltrans crews were working hard to clear Highway 88 westbound around Carson Spur in February 2011 after 12 feet of snow in a week.