From summitpost:
Start from the Bear Lake parking lot and make your way up the Flattop trail. After about a mile, take the junction onto the Fern-Odessa Lake trail. Mosey along the nice trail as it contours alongside the slopes of Flattop and look out for the sign marking the Sourdough backcountry campsite. Shortly after the sign for Sourdough, there will be a small trail that leaves the main trail and heads down past Two Rivers Lake and then to Lake Helene.Skirt the lake on the right and head up the vague rib that goes to the rocky bench below Notchtop.
A faint "trail" leads up towards Notchtop and leads into the gully on the western (left) side of the spire. Ascend it for about 200 vertical feet and keep your eyes peeled for a faint ledge system that leads back left to a ledge on the ridgeline (see photo). Some climbers miss this and end up climbing too high. Rope up on the large ledge and get ready for business.
If you descend the gully like most folks do, you will pass by this spot on the way down.
Ascend 3-4 short pitches of 5.4 enjoyable rock moving up just right of the nose of the South Ridge. There are several broad ledges with good natural horn anchors on each ledge. On the 4th ledge, you'll be below a vertical section of the South Ridge and upward progress is possible, but it is the South Ridge route and rated much harder than the Spiral Route. Now traverse right about 100 yards. You will pass a flaking outcropping and be below the grassy "meadow" that leads up toward the famous notch. Multiple options exist from here and many are harder than 5.4 so choose carefully. The easiest path leads up the grassy ledges on the left side of the meadow. If it feels too hard it is very possible you are off-route. There are about 2 short and one long pitches from the ledge to the notch and the grass and dirt on this section are annoying and potentially dangerous in wet weather. Once in the notch, drop anything you don't need to get to the summit. It is only 4th class from here to the top but it is highly exposed and many parties would still want the security of a rope. Drop over onto the western side of the notch and make your way up a broad rocky ledge above the sheer western face. Make your way carefully across and then back toward the summit via a thin 4th class traverse. The final ridgeline is easy and summit comes as a wonderful surprise. Sit back and enjoy this tiny summit!
