The North Cascades

This pull-off above Diablo Lake is the fastest way to see this note’s whole argument at once. Below you, the Skagit River pools into a reservoir the color of sea glass, an opaque, glowing turquoise that has nothing to do with a clear mountain lake and everything to do with fine rock flour, ground off the mountains upstream by ice and carried down suspended in the current. The lake sits in a canyon cut through some of the oldest rock in this range, a crystalline basement the river has been working since long before there were Cascades to drain. Below and behind you, the concrete of Diablo Dam sits in the same narrow slot the river carved on its own, the gorge here so tight that its granite walls run less than a hundred feet apart. Come for the color; stay to notice how little room the river ever needed to do this much work.

Diablo Dam sits inside the actual gorge the Skagit River cut for itself: solid granite walls that rise about a hundred and sixty feet from the riverbed and, at their narrowest, come to less than a hundred feet apart. Engineers did not choose this spot for scenery. They chose it because the river had already done the hard part, wearing a slot narrow enough to dam cheaply and deep enough to hold a reservoir behind it. Construction ran from 1927 to 1930, and the dam has been generating power for Seattle since 1936, one of three built in sequence up this same canyon. Stand near the structure and it is worth remembering that concrete is the newest thing here by a wide margin; the granite it is wedged into has been in place since long before there were mountains around it to erode. The dam is a short chapter in a much longer argument between this river and this rock. It just happens to be the chapter with a building in it.

From the Diablo Lake Overlook, look south: Ruby Mountain rises directly out of the reservoir, climbing more than a mile of vertical relief in a couple of miles of horizontal distance. That kind of drop is what young, hard country looks like before water has had time to soften it. Ruby Mountain’s own rain and snowmelt split at its summit: the east side drains toward Ross Lake by way of Ruby Creek, the west side drains into Diablo Lake by way of Thunder Creek. Every drop that falls on this one mountain ends up in this note’s river one way or another, just by two different routes. You do not need to climb it to read the story; the shape alone tells you how much elevation the Skagit’s tributaries are cutting through, one small stream at a time.

Pinnacle Peak rises straight out of Diablo Lake’s south shore, a wall of rock more remarkable for how fast it gains height above the water than for its total elevation. Like its neighbors, its runoff drains straight back into the lake and the river below it, a small, steep piece of the same drainage this whole note follows. The Pyramid Lake Trail starts near Diablo Dam and gives a real approach into this group of peaks, climbing through forest and eventually route-finding toward the glacier country above. You do not have to go far up it to feel the trade this canyon makes everywhere: flat ground is scarce, so the trail earns elevation quickly, and the reward is a widening view back down onto the lake and the dam that backs it up. Peaks like this one are the unglamorous half of a river’s story; they are not the water, but they are the reason the water has anywhere steep to fall from.

Paul Bunyans Stump shares the same steep rise as its neighbor Pinnacle Peak, climbing out of Diablo Lake as part of the same chain of summits that runs south toward better-known climbing country. Its name is local color, but its position is the point: it is another piece of evidence for how much elevation the peaks around this lake carry above the water, and how directly their runoff still feeds the Skagit. Seen from across the lake, it reads as one more tooth in a skyline shaped less by any single event than by a long argument between hard rock and moving water, every stream on its flank still cutting, however slowly. This is not a site to visit up close so much as one to read from a distance, ideally paired with Pinnacle Peak and Ruby Mountain, so the shape of the whole basin comes into view at once: a lake pinched between walls this steep on every side.

Ross Dam is a concrete arch rising well over five hundred feet above the Skagit River, and it backs up a reservoir long enough to reach north across the Canadian border. Where Diablo Dam sits wedged into a narrow granite gorge, Ross Dam holds back a much longer, gentler stretch of the river, proof that this canyon does not have one character but several, tight in places and broad in others, depending on what the river found to cut through. Ross Lake is bordered on both sides by protected wilderness, wild country running right down to the shoreline even with the dam at its foot. Standing here, you are looking at the upstream end of a chain of three reservoirs that together have replaced free-flowing river with slack water for a long stretch of the Skagit’s course, the clearest place in this note to see how completely people have answered the river’s argument, at least for now.