It was formed by the collapse of Mount Mazama.
As it is filled almost entirely by snowfall, it is one of the clearest lakes in the world, recording clarity depths of up to 142 feet. The seventh deepest lake in the world, it has no outlet, and Wizard Island rises 764 feet above the surface on its west side. It was formed by the collapse of Mount Mazama. For 10 points—name this body of water, the central feature of a national park in Oregon.
As it is filled almost entirely by snowfall, it is one of the clearest lakes in the world, recording clarity depths of up to 142 feet.
{Crater Lake}