Here the forest is thick and old, with Douglas fir, western red cedar and hemlock towering over the road, and the river below runs milky grey with silt ground off the Emmons Glacier, the largest glacier by area in the contiguous United States.
The Sunrise road is worth the detour if you have the time. It climbs about twenty-five kilometres in long, steady switchbacks to a visitor area at around 1,950 metres, the highest point you can reach by road in Mount Rainier National Park. From the meadows at the top, Rainier fills the sky, a massive dome of ice and rock only a few kilometres away, and in good weather the whole length of the Emmons Glacier is laid out tumbling down its flank. In late July and August the meadows are covered with wildflowers, and marmots whistle from the rocks.
The main road, SR 410, is a fine ride in its own right, with smooth asphalt and long, sweeping curves through the forest. It runs along the eastern edge of the national park, and there is an entrance station at the White River, where you pay the park fee if you are heading up to Sunrise. Further south, the road climbs to Cayuse Pass, where it meets SR 123 heading south toward Ohanapecosh, and then continues east to Chinook Pass.
The weather around Rainier is notoriously changeable. The mountain creates its own weather, and clouds can build quickly even on a sunny day. Rain is common, especially in spring and autumn, and the roads can be wet and slippery under the trees. Snow closes the high roads in winter, typically from November until late May or June. The road to Sunrise opens even later, usually in early July.
There are few services in this area. Sunrise has a seasonal snack bar, but fuel is not available in the park. The nearest towns with fuel are Enumclaw to the northwest, about forty kilometres away, and the small communities along the Naches River to the east. Plan your fuel stops carefully, especially if you are doing a full loop around the mountain.