Sea level rise and increased storm severity is expected to impact coastal lagoons and estuaries, but the magnitude and pattern of response at specific locations is uncertain. The predicted 2015-2016 El Niño along the Pacific Coast provides an invaluable opportunity to observe and document lagoon response, particularly of berms that control mouth dynamics, to large storm events. This project will examine how responses in these two classes of estuaries – those with permanently vs. intermittently open mouths – are affected by factors such as angle of wave attack, watershed size, and lagoon morphology. Results will inform sea level rise planning efforts and help calibrate models, and will be shared through peer-reviewed publication, the California State Coastal Conservancy, the Tijuana NERR, and researcher partners including California Sea Grant Extension.