Mammoth Lakes, and much of the Eastern Sierra above 7,500 feet elevation, awoke to anywhere from one to four inches of heavy, wet snow this morning, with more snow on the way today. Roads are wet and slippery and visibility is poor, due to wind and blowing snow. Chain restrictions are in place on some roads and the high mountain passes in and out of the Eastern Sierra are closed at this time, including the Donner Pass road/I-80 (westbound at Truckee).
As of this morning, according to Caltrans, the following road restrictions are in force:
U.S 395: R1 Chain Controls from 4.5 miles north of Jct. 203 to south Jct. 158
S.R. 203: R1 Chain Control from 2.4 miles west of Jct. 395 to Mammoth Mtn. Inn. Route closed from Mammoth Mtn. Inn to Minaret Vista.
S.R. 120 W: Closed from Tuolumne/Mono County line (Yosemite National Park gate on west side) to four miles west of S.R. 395
S.R. 108/Sonora Pass: Closed due to snow
S.R. 89/Monitor Pass: Closed due to snow
SR 14: High Wind Advisory from LA / Kern Co. line to Red Rock Canyon
Here's a look at this morning's National Weather Service report:
A WINTER STORM WARNING ABOVE 7,500 FEET REMAINS IN EFFECT UNTIL 5 PM
PDT THIS AFTERNOON.
TIMING: HEAVIEST MOUNTAIN SNOW THIS MORNING...WITH SNOW
SHOWERS CONTINUING INTO TOMORROW EVENING.
SNOW ACCUMULATIONS: 6 TO 12 INCHES ABOVE 8000 FEET ALONG THE
SIERRA CREST...WITH 3 TO 6 INCHES ABOVE 7500 FEET ELSEWHERE.
WINDS: SOUTHWEST WINDS 20 TO 30 MPH WITH GUSTS UP TO 55 MPH.
RIDGE GUSTS 100 TO 110 MPH LATE TONIGHT INTO WEDNESDAY
SNOW LEVELS: 8,000 FEET FALLING TO 6500 FEET BY LATE MORNING.
For more updated information, go to Caltrans: http://www.dot.ca.gov/cgi-bin/roads.cgi 
OR the National Weather Service: http://www.wrh.noaa.gov/rev/ 
Call: 1-800-427-7623 for road conditions