Climate variability and Crater Lake water levels

Crater Lake has fluctuated in elevation by 5 meters during the 20th Century. Reasons for these fluctuations were investigated as part of a long-term study of the Crater Lake ecosystem. Lake level changes were found to be closely related to precipitation variations. The lake can be thought of as acting as both a giant precipitation gage and as a large evaporation "pan". Winter snowfall variations are related to variations in the Southern Oscillation Index. Crater Lake offers a unique combination of simple geometry and hydrology, and a long record of supporting data, available nowhere else in the world for a caldera lake.