Starting at the Quinn Meadows Horse Camp, we completed a one-night backpacking loop of Sister's Mirror Lake. On the way up we passed Horse lake, and took the Red Hill trail to Sister's Mirror. About three miles from the Mirror Lakes area, the trail was completely lost under snow, and we relied on GPS to reach to the lake, trail blazes were not visible. On second day, we took the Mirror Lakes trail back towards Quinn Meadows, there was hard pack snow almost the entire way to the trailhead.
If you are thinking of doing this loop before melt out, consider bringing a GPS, spikes, and a topo-trail map. Route-finding would be difficult to impossible without these items.

We camped on the shore of Sister's Mirror lake, in the Mirror Lakes area near South Sister. There's a huge amount of lakes in this area, and you could easily spend a day wandering between them. The lakes range in size from tiny ponds to average-sized lakes like Sister's Mirror. The area is popular for day hikers and backpackers, but due to the snowpack in mid-June, we saw only one other couple camping.

Please note that the Central Cascades Wilderness is a permitted entry zone. The trailheads used in this trip are limited for overnight use.