A glacier inside the Mt Katmai caldera that has formed as a result of Novarupta's eruption in 1912
After the volcanic activity ceased on Mount Katmai, a glacier formed on the inside wall of the caldera. This glacier, which now extends down to the edge of the caldera lake, is perhaps the only glacier in the world having a known date of origin. Glacial features within Katmai preserve a complete sequence of Wisconsin and Recent (Alaskan) glaciation.