Up here, near the treeline, the trees give up. Around Rainbow Curve and on toward Forest Canyon Overlook, the spruce and fir that lined the lower road shrink into twisted, stunted shapes called krummholz, bent and sheared by the wind, and then disappear altogether, leaving a vast, open world of tundra, rock and sky. The views are enormous: deep glacial valleys, the jagged peaks of the Continental Divide, and on a clear day the plains stretching away to the east. You are above 11,000 feet, and the air is thin and cold.
The alpine tundra is one of the most fragile environments in the park, and it is protected with care. Plants here grow slowly, with a growing season of only a few weeks a year, and a single footstep can damage them for decades, so stay on the paths. In summer the tundra is covered in tiny wildflowers, alpine forget-me-nots, moss campion and sky pilot, and you might see marmots sunning themselves on rocks, pikas collecting grass for the winter, and bighorn sheep or elk grazing on the high slopes. Ptarmigan, whose feathers turn white in winter, are almost invisible against the rocks.
Forest Canyon Overlook, a short walk from the road, looks down into a deep valley carved by glaciers, with the Big Thompson River at its bottom and the peaks of the Divide above. Further on, the road reaches its highest point, at 12,183 feet, and the Alpine Visitor Center, at the top of a steep cirque, has exhibits, food, toilets and views across the park.
The riding is spectacular but demanding, not because the road is technical, but because of the conditions. The curves are smooth and the grades gentle, but there are no guardrails in places, the drops are steep, and the weather can change in minutes. On summer afternoons, storm cells build over the Divide with lightning, hail and strong winds, and you do not want to be on the exposed tundra when lightning strikes. Snow can fall at any time of year, and the road is closed from mid-October to late May. The altitude can also cause headaches, breathlessness and fatigue, so take it easy, drink plenty of water, and ride early in the day. Fuel is not sold inside the park, so fill up in Estes Park or Grand Lake.