See crews clear Sonora, Tioga passes: ‘Deep enough to stop snow blower in its tracks’

Working seven days a week, Caltrans maintenance crews continue to clear roads covered in eight feet of snow at Sonora Pass, and have plowed to within 5.8 miles of the eastern entrance of Yosemite National Park at Tioga Pass.

New video shows significant progress being made in removing the snowpack from Highway 108 (Sonora Pass) and Highway 120 (Tioga Pass) since their efforts began in late April. Caltrans has not been able to provide an estimated time for opening either of the southern Sierra Nevada passes.

The 9,943-foot-high Tioga Pass serves as the eastern entrance to Yosemite. Nearly as high in elevation, Sonora Pass connects the town of Sonora to the west with Bridgeport to. the east.

Caltrans gave some insight into the prodigious amount of work involved in plowing the snow-covered roads.

“The snow on the highway ... is deep enough to stop a snow blower in its tracks,” Caltrans District 9 reported on its Instagram account. “To clear the road as efficiently as possible, maintenance crews are utilizing a snowcat with plow attachment to drive on top of the snowpack and push it down to the pavement below. This method reduces the depth of the snow on the highway to a low enough point where our snow blowers can drive through and clear the road.”

The snow blowers being utilized at this snow depth can clear up to a half-mile of snow a day, but the deepest snow is yet to come, Caltrans said.

“The snow blower (used) is the ‘pioneer’ snow blower,” Caltrans said on Instagram. “Its job is to push forward on the highway, clearing snow from the double-yellow line. With that line exposed, two more snowplows can follow behind it, clearing the snow to the pavement fog lines. The amount of snow on the highway is expected to get deeper as crews approach the county line.”

The new video (above) shows multiple snowblowers working to clear Highway 108 from the Mono County side. Crews are still about two and a half miles away from the summit, Caltrans reported.

Even though snow blowers are trying to clear down to the pavement on most of Sonora Pass, many areas along the highways are covered with a solid layer of ice, called Sierra Cement.

In addition, crews face the possibility of hitting debris mixed with the snow, including rocks and fallen trees.

Meanwhile Caltrans District 10 is trying to clear Highway 4 at Ebbetts Pass in Apline County. Faced with deep snow and steep terrain, the transportation agency said there is no estimated time of reopening.

See crews take on a wall of snow blocking Tioga Pass across Sierra. ‘It’s gonna be a while’