This 5,324ft Cascade Pass is closed in winter, but the winding highway (following an 1860s wagon route) is well worth a drive during the snowless months. A 65sq mi lava flow surrounds the Dee Wright Memorial Observatory, above the summit parking area; the view extends across six Cascade peaks and numerous smaller volcanic cones and craters. The .5mi Lava River Trail is a self-guided interpretive walk through lava gutters and crevasses.The Pacific Crest National Scenic Trail, linking Canada with Mexico down the Cascade-Sierra crest, crosses McKenzie Pass and offers the most direct hiking access to the Three Sisters Wilderness, immediately south. Nine sizable glaciers and numerous small lakes cloak the heights of these volcanic cones-the North (10,085ft), Middle (10,047ft) and South (10,358ft) Sisters.