YOSEMITE NATIONAL PARK -- Between a granite cliff and the Merced River, workers carefully rebuild a crumbling road.
Massive digging equipment rumbles back and forth in the snow on the 11-foot-wide road, snaking through a steep canyon where the wind whistles and the sun doesn't shine even at midday.
Yosemite National Park can't wait for warmer weather to do this long-delayed job. For one thing, the Merced runs low in winter, so now is the best time to build a protective wall down to the riverbed.
More importantly, though, El Portal Road could soon collapse into the river under the weight of cars and busloads of tourists -- several hundred thousand vehicles pass through here each year.
"This is for the protection of visitors, residents and people who travel every day into the park to work," said Yosemite spokesman Scott Gediman. "The road is not safe."
But safety and river levels aren't the only reasons that this quarter-mile stretch has become a big problem. A legal fight with environmentalists delayed the project and frustrated park efforts, officials said.
The problem began after a devastating 1997 flood damaged 15 miles of the El Portal Road. The National Park Service rebuilt all but the last mile of road before environmentalists sued almost nine years ago.
A judge stopped work on the remaining one-mile section, requiring Yosemite officials to first finish a river protection plan. That plan has twice been rejected in federal court and now is under appeal.
But work on the quarter-mile stretch of the disputed segment is being allowed under emergency provisions.
Park officials said the dangerous quarter-mile would have been fixed long ago if not for the legal action, which was filed in 1999 by the Sierra Club and Mariposans for Environmentally Responsible Growth.
The activists involved have said they never stood in the way of repairing a dangerous road. If the work was needed, they said, it could have been done at any point.
They said their complaint was that the rebuilding of the first 14 miles was too extensive. Activists said the park service unnecessarily chopped down large trees, paved over sensitive riverbanks and widened the road for buses and recreational vehicles.
The activists have not filed new legal action against the quarter-mile project, saying they would not oppose such emergency action. But they said they think the repairs are going too far.
"A lot of people are very, very upset about the amount of vegetation that has been taken out," said Bridget Kerr, a member of Friends of Yosemite Valley, which has long complained about road repairs and has filed separate action over the river plan. "They're changing the character of that short stretch of road."
Yosemite officials said the goal is to make the road safe. They said the road will be only slightly widened.
"It still will not be wide enough by federal highway standards," said park engineer Mike Pieper. "You can see why. This is a very narrow place."
The road is an old stagecoach route that connected El Portal with Yosemite Valley in 1907, officials said. The park started building the paved road in 1918 and completed it eight years later.
The route has been known as the "all-year highway" for the past eight decades because it is a low-elevation approach to Yosemite Valley. Often when storms cause delays on other routes into the park, El Portal Road has little or no snow.
After the 1997 flood, the river began washing out holes beneath the quarter-mile section now under construction. Officials began making emergency repairs each year.
The Federal Highway Administration two years ago decided the quarter-mile stretch had become too dangerous and set aside $7 million for the permanent repair.
The nonprofit group Transportation Involves Everyone, with a field office in Midpines, said it is a relief to see the work.
"It's a very complex project," said director Ken Gosting. "We're just glad to see it's proceeding."
The work is an inconvenience for those who use the road daily, but motorists are still using the road. They sometimes must wait up to 30 minutes for access to the section.
Though workers are moving cautiously on this icy, slanted landscape, they must finish this job before the Merced River rises with spring snowmelt. The swift river could wipe away their progress if they have not finished.
There are also large electricity and sewage lines beneath the road. For the project, workers have set up a temporary sewage bypass line to avert any possible spills during the construction.
"That's a 16-inch pipe for the sewage," Pieper said. "It would be a big problem if that pipe opened up in the river."
Beyond the sewage issue, access to Yosemite Valley would be restricted if the road is closed for any length of time. El Portal Road funnels summer traffic into Yosemite Valley from three entrances -- Arch Rock, Big Oak Flat and Tioga Pass.
Of the 3.3 million people who annually visit the park, nearly three-quarters of them pass through Yosemite Valley, which offers spectacular views of such landmarks as El Capitan, Half Dome and Yosemite Falls.
"The only way in would be from Highway 41 to the south," said Gediman. "That would be a major impact."