UPDATE May 6, 2021
Caltrans District 10 announced this morning that SR-108/Sonora Pass will OPEN today, May 6th, at noon. Last year Sonora Pass opened on May 15, 2020.
Caltrans District 10 manages three trans-Sierra passes in the central Sierra that are closed during winter and generally open in spring: Ebbetts Pass/SR-4 in Alpine County, Sonora Pass/SR-108 (Tuolumne County), and Monitor Pass/SR-89 (Alpine County). Caltrans recognizes the importance of this route to the region’s economy, which depends a great deal on tourism.
Update from May 5, 2021: This afternoon, Caltrans District 10, which oversees Highway 108 (Sonora Pass) and Highway 4 (Ebbetts Pass), provided some updated highway opening information for these trans-Sierra routes. According to Caltrans, they are completing paving work on both roads. Ebbetts Pass has significant repaving work to be done that will begin on May 10, with the goal of opening Highway 4 for the Memorial Day weekend. Repaving and maintenance work is nearly complete on Highway 108, and Caltrans hopes to open it this coming weekend, and will have an announcement soon regarding opening.
Original Post from April 16, 2021: Last week The California Department of Transportation (Caltrans) opened Monitor Pass (Hwy 89) over the Sierra Nevada, with the focus moving to Ebbetts Pass (Hwy 4) and Sonora Pass (Hwy 108) Monitor Pass offers another way to Hwy 395 on the East Side, opening up access to Sierra spring skiing at Mammoth Mountain and in the backcountry. Caltrans traditionally plans to open Sonora and Ebbetts Passes by Memorial Day weekend, but with lower snow during the 2020-2021 winter, and the April 24th stream fishing opener, they hope to open both of them earlier.
Highway 108 over Sonora Pass leaves Hwy 49 in Sonora, CA, and rolls about 50 miles up to the Tuolumne/Mono County line at 9624′, before dropping 16 miles down to Highway 395 at Sonora Junction north of Bridgeport, CA. Highway 108 is the access for Dodge Ridge Ski Area, Eagle Meadows, Kennedy Meadows, Sonora Pass, and Leavitt Lake, all of which provide jumping-off points for backcountry skiing. Above Kennedy Meadows, this is a steep, winding, narrow, two-lane road. As of April 13, 2021, Caltrans crews had opened lower elevation, with current closures near Leavitt Lake Road on the east side and Eagle Meadows on the west side. Eastside crews have reached the top of the pass, while west side crews have reached Kennedy Meadows.
These are the dates that Sonora Pass closed for the winter and then opened up again in the spring, going back to 2010.
Highway 4 over Ebbetts Pass leaves Highway 49 in Angel’s Camp, CA, and travels 61 miles from Arnold, CA over the 8736′ pass to Markleeville, CA. You can access Highway 89 to Highway 395 over Monitor Pass before you get to Markleeville. Highway 4 accesses Bear Valley Mountain Resort, Lake Alpine, Highland Lakes, and Ebbetts Pass. Above Lake Alpine, this is a steep, narrow, winding road, often with only a single lane. The current west side closer is at the east end of Lake Alpine, with crews clearing to near Mosquito Lake.
These are the dates that Ebbetts Pass closed for the winter and then opened up again in the spring, going back to 2010.