Japan's Mt. Tateyama in the Hida Mountains is considered one of the snowiest spots on the planet. More than 125 feet of snow can fall on the region in a single year. Route 6 runs right through the Mt. Tateyama but just before you enter the tunnel, there's a 1/4 mile piece of highway called yuki-no-otani, or in English, Snow Canyon. The Toyama Prefectural Road Public Corporation is responsible for plowing the road after winter. It takes about a month. From Atlas Obscura:
At the Snow Canyon, the non-human star of the show is the HTR608, a rotary snow blower made by the Nichijo company—the 608 refers to the 608-horsepower engine. The HTR608 can plow through snow up to six feet high. The rotating bar helps pull snow into the machine, and a powerful propeller ejects it out of an aerodynamic pipe that can spray the snow nearly 50 feet high and half a football field to the side. But before this monster can even begin its job on the Snow Canyon, a series of prior snow-clearing events must take place.
Mt. Tateyama receives too much snow and is too remote to receive continual snow plow treatment, thus for much of the winter snow is allowed to bury the pass. Sometime in early March, a bulldozer specially equipped with both a GPS and a mobile satellite phone is sent up the mountain and over the Snow Canyon. The GPS and sat phone work in tandem to provide the driver a detailed video screen image of the dozer’s location in relation to the center of the snow-buried highway. This driver’s job is not to clear snow, but simply to lay out an accurate track of the road itself. Following the GPS dozer is a team of dozers that will begin the clearing operations. The first bulldozers will push and carry the snow forward, to areas where depths are lower and it can be pushed aside or dumped. Backhoes are used to help widen the road. When the bulldozers have come within six feet or less of the road, the rotary blowers can begin their work, and help to at last reveal the long buried asphalt.
"How to Clear a Path Through 60 Feet of Snow, Japanese Style" by Justin Nobel (Atlas Obscura)
(top image by PIETRO ZANARINI; below from TATEYAMA KUROBE ALPINE ROUTE SNOW REMOVAL ASSOCIATION.)