Geo 892: Lost Lake's "Drain Hole"

The hole is both smaller and shallower than I expected, and at this time of year, well back from the water's edge. The lake bed appears to be composed of relatively thin laminae of ash and lapilli, and well lithified. This isn't surprising, given its location near the crest of the active section of the Cascades, but it isn't what I was expecting. Rubbly basalt and basaltic andesite dominate much of the central Oregon Cascades between our location here, along Highway 20, and McKenzie Pass along Rte. 242. However, my suspicion is that under these layers of tephra, the lava rubble is present; that would allow the water draining through this sinkhole to move to the water table, and, ultimately, re-emerge at Clear Lake.

Photo unmodified. September 7, 2016. ZoomEarth location. (Location approximate- can't resolve hole.)