Road Riding in Glacier National Park

 Heath Korvola / Aurora / Getty Images

Going-to-the-Sun Road, the highest in Glacier National Park, ascends like a one-way route to the sky, gaining a grueling 3,400 vertical feet amid some of the most pristine glacier-carved valleys in the West. And with hairpin turns and 180-degree switchbacks, it's a road rider's paradise.

In the summer, a steady stream of cars, RVs, and buses make the road too dangerous to ride. But for four to six weeks in late May and June, the cyclists get it to themselves. "The road is closed in the winter," says local rider Pete Thomas. "Come spring, it takes the park service six to eight weeks to plow it out. We wait for that all year." Last spring I was in Whitefish, Montana, on the west side of the park, when that window opened: The road was clear almost to Logan Pass, the summit at mile 32. We set off early the next morning.

The trail follows the churning McDonald Creek through the evergreen valley, climbing gradually at first against a panoramic backdrop of giant peaks and dramatic waterfalls. The road gets increasingly treacherous, and we dodged piles of gravel, mud, and branches left by winter avalanches. After about three hours, both sides of the road were penned in by progressively taller walls of snow and then became impassable. We had reached the top.

We pulled on arm warmers and windbreakers and switched directions, flying down the middle of the road at speeds of up to 50 miles per hour. Banking around a bend, I saw that my friends had stopped, and I grabbed the breaks hard. Two grizzly bear cubs were lumbering behind their mother in the valley below. We were down in less than an hour, planning another ride for the next day, before the magical window closed.