Pinnacle Ridge is probably the most forgotten peak on the Wyoming 13ers list. Nestled on the jagged ridge just south of Gannett Peak, it is overlooked by just about everyone who ventures into the Dinwoody Glacier cirque. Hundreds of people will stand atop Gannett Peak each summer, and even more will find themselves making the long hike out after failed attempts, however on most years there will be a big fat goose egg for the times Pinnacle Ridge sees a visitor on its summit. The peak is actually situated about halfway between Gannett and Woodrow Wilson right on the divide, and for anyone who does find themselves on this peak there's a very high chance they are working on the Wyoming 13ers. It makes a great combination with Woodrow Wilson.
The standard approach is via the Glacier Trail from the Torrey Lakes trailhead. To get there head four miles east of Dubois, turn south from highway 26/287 and follow the improved dirt road (FS #411; passable in cars) eight miles past Trail Lake Ranch to its end. The Glacier Trail is then taken for approximately 21 miles to the Dinwoody moraine.
Alternatively, the area can also be reached from the Elkhart Park trailhead via the route over Bonney Pass. This entails a trek of a similar distance but adds the high crossing of the divide and the complete descent of Dinwoody Glacier. If all you're after is Febbas and you're on a limited time schedule, the tribal outfitter from the Wind River reservation (307-332-7207) can take you up a jeep road and drop you at an eastern extremity of Horse Ridge near the forest service boundary. This fixes you to a strict schedule and will cost in the hundreds after the permits are added. At the end of the day you'll want to reach a camp on the Dinwoody Moraine.
From camp on the Dinwoody Moraine, the easiest route to the summit involves starting up the northernmost arm of the Dinwoody Glacier, as per the start of the normal route up Gannett. However, instead of cutting right up the scree/talus slope to the rocky ridge separating the Dinwoody from the Gooseneck Glaciers, continue west up the northern arm of the Dinwoody. In later season, there will be bare ice exposed on the lower part of the glacier, and the easiest way will be to skirt the far north edge where it meets the rock. Crevasses are fond here as well, so watch out for any suspicious snow bridges when bare ice is visible. Once you reach 12,200 feet in elevation, the glacier transitions into a lower angle, more uniformly snow covered glacier, and you can make an ascending traverse in a SW direction, turning more westwardly as you near the edge of the next rock ridge to the south.
Continue ascending the snow, aiming for a long, fairly wide snow finger extending up to a tiny col on the divide. This is the col directly north of Pinnacle Ridge. Reaching the summit looks improbable while on the glacier, but rest assured, the class 4 route is hidden behind the east facing cliffs that you see from the glacier. The final 200 feet up to the 13290 foot col are on steeper snow in the 40-45 degree range, however the early sun allows it to normally soften up pretty quickly (bring crampons!) Once you reach the col, cross over to the west side slightly and ascend a few feet to the south and you'll see the final north facing steep scramble present itself just around the small corner. Climb an obvious loose gully until it ends 20 feet below the summit ridge, then cut right and traverse a short ways on some delicate ledgy slabs (crux). The easiest way up the final 20 feet to the summit boulder will be obvious (class 4). The summit boulder is a truck sized rock that requires an exposed bouldery move to surmount, and is only big enough for one person to sit atop at a time. You get an interesting perspective of both Gannett and Woodrow Wilson from here.
No Red tape. Practice leave no trace. The water sources on the Dinwoody Moraine are quite murky, so some people like to have a water filter...although I didn't feel the need for one.
Summer season in the Wind Rivers is generally July-September with snow lingering on the higher trails into July. A snow storm is traditional between the last week of August and the second week of September. This is normally followed by a dry period with crisp temperatures for 1-4 weeks. On glacier routes, crevasses are hidden in June and begin opening sometime in July. Because the Trail Lake/Torrey trailhead is below 8000', on the dry side of the range (the glaciers above absorb the majority of the storms, causing a rain shadow near Dubois), the trailhead can surprisingly be reached almost year round; the exception being during heavy spring storms. The downside for ski approaches is that several miles must often be hiked before significant snow is reached.
This map shows the route up Pinnacle Ridge described above with a brown line from a typical camp on the Dinwoody moraine. Combining with the north couloir route of Mount Woodrow Wilson is also displayed.