These are areas deemed to be at risk during an "extreme tsunami," which is a new class of seismic event that has been modeled but not observed historically. Data are intended to be used for evacuation planning and natural hazard mitigation. Boundaries are based on peer review of inundation models provided by University of Hawaiʻi researchers and the operational needs of each county's First Responders and the Emergency Management Community. For most Tsunami Warnings, evacuate out of the tsunami evacuation zones; in the unlikely case of an "Extreme Tsunami" Warning, evacuate out of both the tsunami evacuation zones and the extreme tsunami evacuation zones.
Extreme tsunami evacuation zones only available for the islands of Kauaʻi, Lānaʻi, Maui, Molokaʻi, Niʻihau, and Oʻahu. Boundaries for Hawaiʻi Island are in development but have not yet been completed.