Wizard Island
is actually the top of a volcano that formed after the collapse of Mt. Mazama
following it's eruption 7,700 years ago. A new volcano formed inside the
crater and became Wizard Island when the caldera filled with water. Lava
flows from this volcano probably helped seal the caldera so that it filled
with water to form Crater Lake. The lake appears to have reached a stable
depth with annual snowmelt and rainfall equaling what seeps from the lake.
There is no outlet from the lake other than this seepage. This is also one
of the purest lakes in the world.
