Lost Lake, located in central Oregon, is known for rapidly draining every year through a six-foot (two-meter) wide hole in the lake's bottom (as shown in the video). Early in the following spring, however, the lake fills up again, as snowmelt from the surrounding mountains accumulates faster than water can drain out through the hole. That hole is really a
lava tube - a geologic feature made when lava cools around the edges of a river of molten rock. After the hot lava drains away, it can leave an empty space.
