Half dome and Clouds Rest with snow in Yosemite National Park, CA today at sunrise.

Overnight snowfall and a forecast including a Winter Weather Advisory today closed 3 mountain passes in California at 11:30pm last night.

Mammoth Mountain, CA mid-mountain today at sunrise.

California Mountain Passes Currently Closed:

9,945′ Tioga Pass (hwy 120)

SR 120
[IN THE CENTRAL CALIFORNIA AREA & SIERRA NEVADA]
IS CLOSED FROM CRANE FLAT TO 5 MI WEST OF THE JCT OF US 395 /TIOGA PASS/
(TUOLUMNE, MONO CO) - DUE TO SNOW - MOTORISTS ARE ADVISED TO USE AN ALTERNATE 
ROUTE - Caltrans, today

9,624′ Sonora Pass (hwy 108)

SR 108
[IN THE CENTRAL CALIFORNIA AREA & SIERRA NEVADA]
IS CLOSED FROM 26.4 MI EAST OF STRAWBERRY (TUOLUMNE CO) TO 3 MI WEST OF
THE JCT OF US 395 (MONO CO) /SONORA PASS/ - DUE TO SNOW - MOTORISTS ARE ADVISED
TO USE AN ALTERNATE ROUTE - Caltrans, today

8,631′ Ebbetts Pass (hwy 4)

SR 4
[IN THE CENTRAL CALIFORNIA AREA]
IS CLOSED FROM 0.5 MI EAST OF THE JCT OF SR 207 /MT REBA TURNOFF/ TO THE 
JCT OF SR 89 /EBBETTS PASS/ (ALPINE CO) - DUE TO SNOW - MOTORISTS ARE ADVISED 
TO USE AN ALTERNATE ROUTE - Caltrans, today

Map showing locations of Tioga, Sonora, Ebbetts, and Monitor passes in California.

NOAA has issued a Winter Weather Advisory for California today that is calling for 3-8″ of snowfall between 8am and 11pm today.

* SNOW ACCUMULATIONS...3 to 6 inches possible above 7000 feet with up to 8 inches 
over higher Sierra peaks. - NOAA Sacramento, CA today

This is California’s first snowfall of the season.

Snow in Tuolumne meadows in Yosemite’s high country today at sunrise.

Winter Weather Advisory for California:

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sacramento CA
404 AM PDT Thu Sep 21 2017

...Unseasonably Early Snow Over Northern Sierra Today into Early
Tonight...

.An unseasonably cool weather system will bring early season snow
to the Northern Sierra today into early tonight. Snow levels are
expected to range from 6000 to 7000 feet with main snow
accumulations above 7000 feet. There could be 3 to 6 inches of
snow along Interstate 80 above 7000 feet...impacting areas near
Donner pass. Up to 8 inches is possible over higher peaks of the
Sierra Nevada. Motorists traveling into these areas today and
early tonight should be prepared for slick roads.

West Slope Northern Sierra Nevada-
Including the city of Blue Canyon
404 AM PDT Thu Sep 21 2017

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM THIS MORNING TO
11 PM PDT THIS EVENING...

The National Weather Service in Sacramento has issued a Winter
Weather Advisory for early season snow, which is in effect from 8
AM PDT this morning to 11 PM PDT this evening.

* TIMING...From this morning into early tonight.

* MAIN IMPACT...Slick roads may bring spin-outs and longer travel
  times. Outdoor events and recreation may be impacted.

* LOCATIONS...Western Sierra Slopes, Interstate 80 impacting
  areas near Donner pass, Highway 50, high elevation campgrounds
  and trails.

* SNOW ACCUMULATIONS...3 to 6 inches possible above 7000 feet with
  up to 8 inches over higher Sierra peaks.