Katmai Caldera Aerial view southward overlooking Katmai caldera, formed by collapse in 1912, when Novarupta erupted 10 km away. The steep walls of the caldera truncate glacier-filled valleys that once continued upward to the summits of two distinct edifices, Northeast Katmai (closer wall) and Southwest Katmai (far wall). The "beheaded" glaciers are still active. Lakewater, now 250 m deep, has apparently reached a steady state and is no longer rising. Photo by Judy Fierstein; August, 1999.