The southwest ridge route on Bastion Peak uses a glacier on the southeast face to reach the Continental Divide between Bastion Peak and its southern neighbor, Rampart Peak. The true summit of Bastion is less eye-catching than its craggy northeast buttress (13,470 feet above sea level), which cuts a striking figure from Grasshopper Glacier to the north (Photo 1) and from the upper reaches of Gannett Creek (Photo 2). A formidable, exposed ridge (Photo 3) separates the two summits.
No trails pass near Bastion Peak. There are at least two reasonable approaches to the southwest ridge from the east side of the Continental Divide. Both require several days’ worth of backcountry travel, at least one day of which is off trail.
From the north, one can approach the peak via beautiful, nearly flat Grasshopper Glacier: from the southern head of the glacier, continue in a southerly direction over a gentle 12,200-foot pass, then descend a small glacier that feeds the headwaters of Gannett Creek. At about 11,440 feet above sea level along Gannett Creek, below the permanent snow, there’s a level campsite near the base of the route (see map).
Approaching from the south, one can leave the Glacier Trail where it crosses Gannett Creek and continue through talus along the north side of the creek to this same campsite. In August 2008 neither approach had consistent cairns, but the routefinding from Grasshopper Glacier or the easy-to-follow Glacier Trail is straightforward.
From the 11,440-foot campsite, ascend west on the glacier draped on Bastion's southeast face. By angling from south to north on the lower half you can avoid most crevasses (Photo 4). The first 500 vertical feet involve a maximum slope of about 40°; the second 500 feet are much gentler. After that, it’s possible to reach the flat, dry southwest ridge connecting Bastion with Rampart Peak by negotiating another 500 vertical feet of glacier (Photo 5) at no more than 50°. When you step off of the glacier onto the dry ridge, avoid the loose, sandy scree, or you’ll treadmill and send loose rocks hurtling downward. Instead, look for solid talus to climber’s left.
Once you’ve cleared the lip of the cirque, it’s an easy, class-2 walk northeast to the summit proper. The views are spectacular (Photo 6): on a clear day you can see at least 5 of Wyoming’s other 10 highest peaks, including the Grand Teton.
To descend, retrace your steps. The steeper parts of the glacier offer superb glissading. As a result, it’s possible for mere mortals to reach the summit and return to the 11,440-foot camp in three hours.
We used ice axes, crampons, and helmets. Although easy to climb and descend, the glacier has several crevasses big enough to hurt, so glacier travel precautions are in order. We tied into an 8-mm rope and carried a picket.