07 August 2013

Green Lakes, Three Sisters Wilderness

Broken Top with the southern-most of
the Green Lakes in the foreground.
Last week we took the kids on their first backpacking trip to the Three Sisters Wilderness in the central Oregon Cascades. During the summer of 2012, I took two day trips to the northern side of the wilderness near the Mathieu lakes area, so this time we ventured into the eastern part, heading west from Bend.

The Green lakes trail starts near where Fall Creek empties into a broad alpine expanse that is part meadow and part lake. The trail tends to closely follow Fall Creek northward where it tumbles out of a valley. At the height of the summer the cold water was still moving briskly and there were a few waterfalls and rapids along the several miles between the trail head and the point where the creek emerges from the Green Lakes basin. Along the banks of the creek, there were myriad flowers and wetland plants including orange and pink paintbrushes and Delphiniums.

At about 6500 foot elevation, the valley opens northward into a large basin that is home to the three Green lakes. The basin is a beautiful jewel nestled in between two of the tallest peaks in the Oregon Cascades: South Sisters to the northwest (10,358 ft) and Broken Top to the east (9175 ft). From different points within the basin, Mt Bachelor (9068 ft) and one of the companion Sister peaks are also visible. Both South Sisters and Broken Top have small glaciers according my copy of a USFS map. However, while South Sisters had some lingering patches of snow, it was hard to consider these glaciers per se. A warming climate is threatening the persistence of glaciers worldwide, and I wonder if these smaller glaciers in the Pacific Northwest are particularly vulnerable to rapid demise.


Fall Creek
Our camp was located just some 100 m east of Fall Creek near the point where it begins to leave the basin and tumble down into the valley that we had ascended. In this area the creek was lined with willows growing as dense shrubs no more than 1-2 m high. We also found numerous black tadpoles in the shallow creek, with fat oval bodies and eel-like tails. The older kids had fun catching them.

Immediately west of the valley was an extensive lava field with little apparent vegetation. The field had dark boulders of shiny obsidian mixed with the milder colors of volcanism: light and medium greys and orange. We noted that many of the rocks of the lightest grey color were extremely light weight for their size; I found that one could easily snap the smaller ones in half.


Plants along the edge of Fall Creek. I don't
know this species, but the flowers had the
very distinct smell of watermelons!
The slopes of South Sisters itself had little vegetation, but were composed of some scattered snow patches, fields of grey volcanic rubble and a streak of reddish rock near the summit. Along much of the trail, the forest seemed to be composed mostly of mountain hemlock, though there were firs and pines present as well. I do not recall seeing a single broadleaved tree. Much of the remaining vegetation was low lying shrubs and herbaceous plants, particularly in the more open volcanic meadows around Green lakes. Despite the rugged landscape, many plant species were in bloom, giving the harsh terrain an elegant vibrancy.



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