Mount Thielsen is the first thing you see, and it is hard to look at anything else. The mountain rises behind Diamond Lake in the Oregon Cascades, a needle of dark volcanic rock about 2,800 metres high, so sharp and so often struck by lightning that it is known as the lightning rod of the Cascades. It is an old volcano, eroded by glaciers until only the plug of hardened lava in the core remains. The lake sits at around 1,600 metres in a forested basin, with the broader bulk of Mount Bailey on its other side, and the water reflects both peaks on a calm morning.
Diamond Lake is a summer playground, with cabins, campgrounds, a resort and a bike path around the shore, and in winter it becomes a snowmobiling and skiing centre. The lake is a popular trout fishery, and the water can turn green with algae in late summer, which sometimes closes it to swimming. The surrounding forest is ponderosa and lodgepole pine, with mountain hemlock higher up, and the air smells of resin and dust. Mosquitoes in June and July can be fierce.
The road is the Rogue-Umpqua Scenic Byway, and the stretch of Oregon Route 138 that passes the lake is one of the best rides in the Cascades. Heading west, it follows the North Umpqua River down a long, forested canyon with waterfalls, clear green pools and a string of campgrounds, a smooth road with long gentle bends and little traffic. East of the lake, a short road leads to the north entrance of Crater Lake National Park, with its famous deep blue water. Snow closes the park roads from late autumn into early summer, and the high routes can be icy in the mornings even in June.
Fuel and services around the lake are limited and seasonal, so it is best to take on petrol in a larger town before the climb, rather than counting on a pump at the resort. The valley below has more choice, with small towns along the river offering coffee, food and basic repairs. A cafe in the lodge is a good place for a warm meal after a cold ride.
Summer evenings at the lake are pleasant, but nights are cold, and frost is possible even in August. Bring a warm layer, and be careful on the gravel parking areas, where sand and pine needles make for slippery footing.