Geo 897: A Last Glance at the Lost Lake Drain Hole

I'd say the hole is about 4-5 feet across, less than the 6 foot diameter reported in most of the stories I've read, and 2-3 feet deep. As I mentioned in the first post about this location, the layers of ash and lapilli are probably responsible for creating a tough and poorly permeable lake bed. It does seem likely to me that this is some kind of sinkhole, but I don't have any sense of what might have created the void that the rock collapsed into. The mafic lava flows in the area have enormous amounts of void space in their rubbly surfaces, and I don't feel that a lava tube is a necessary conclusion, though it might be the correct one. Perhaps someday we'll find out.

To put this in a broader context, if you're traveling across Santiam Pass, and you have a little time, this is well worth the rugged, pot-holey drive in (I'd say okay for smaller cars, just take it slow.) at least once. It's not something I'm going to feel I need to do every summer, but I'd like to visit in the late spring sometime, and given the new hole, it might be worth stopping every few years or so, to see if the area evolves further.

Photo unmodified. September 7, 2016. ZoomEarth location.