This trail features two lakes with quite different characters, a rocky high pass, and excellent Rainier summit views. If you turn around at the lower lake, it's 4.6 miles with 1980' elevation gain. To the upper lake but skipping Sourdough Gap is 5.8 miles and 2340'.

From the trailhead to Lower Crystal Lake is a forested hike. The path switchbacks up a steep hillside, continues past the Crystal Peak turnoff on the right, then straightens out as the incline eases and trees decrease in size. The lower lake is small, gentle, and lovely.

Between the two lakes you will find a host of wildflowers earlier in the season, or berries later on. This is the rain shadow side of the mountain, so plants are separated by patches of dry dirt, very unlike the dense vegetation of Rainier's south or west slopes.

Upper Crystal Lake is much larger than the lower one, and backed by steep crags. A sign indicates that the campsite is to the right, while the trail heading left around the lake is unsigned. Head left regardless, because the best of this hike is yet to come.

As you climb above the lake, Rainier's summit comes into view behind you. You'll want to turn around every few paces to marvel at how it continues to grow as you continue to ascend. Sourdough Gap is a dramatic place of jagged rocks and a big view down the valley of Morse Creek, before which you'll pass a sign marking the edge of Mount Rainier National Park. Congratulations, you've joined up with the Sheep Lake and Sourdough Gap trail!