Georges Bank shelters much of the Maine coast from a major tsunami threat. However, small but dangerous tsunami waves are possible. Strong currents generated by rapid and chaotic changes of water levels in the Gulf of Maine present the greatest threat to Maine. Inundation of land areas is possible at the time of high tide. However, this threat is not as severe in Maine as the threat of the fluctuation of water changes.
TSUNAMI WATCHES, WARNINGS, AND ADVISORIES
The National Tsunami Warning Center (NTWC) in Palmer, Alaska, issues tsunami watches, warnings, and advisories for the East Coast. The Center monitors seismic activity throughout the world and determines the likelihood of tsunamis based on that activity.
A tsunami watch is issued based on seismic information when a tsunami is possible for a particular location. The watch provides advance notification to areas that possibly could be impacted by a destructive tsunami, and the recommended action is to stay alert for more information. As more information becomes available, the watch may be changed to a warning or advisory, or cancelled. During a watch, the Tsunami Warning Center will issue updated information at least every hour.
A tsunami advisory is issued when a tsunami with the potential to generate strong currents or waves dangerous to those in or very near the water is imminent, expected, or occurring. Inundation of land areas is not expected in the case of an advisory, though the advisory may be upgrade, downgraded, extended, or cancelled as appropriate. Recommended actions for those in an advisory area are get off beaches and to evacuate harbors and marinas if there is time to safely do so.
A tsunami warning is issued when a tsunami with the potential to generate widespread inundation is imminent, expected, or occurring. In the case of a tsunami warning, it is recommended that local officials evacuate low lying areas and reposition ships to deeper waters when there is time to do so. Warnings may be updated, adjusted geographically, downgraded, or canceled.
The National Tsunami Warning Center issues information statements to keep the public informed of seismic situations when a watch, warning, or advisory has been issued by the NTWS for another section of the ocean.
During a tsunami event affecting the Gulf of Maine, the National Weather Services offices in Gray and Caribou will issue special weather statements that provide updated information on the event and its impact along the northern New England coast.
STAYING SAFE IN THE GULF OF MAINE
Strong tsunami-generated currents along the coast and in the channels and bays of Maine present the greatest threat to those in the Gulf of Maine. Tsunamis generated in the Gulf of Maine are not likely to provide significant warning time. If water levels unexpectedly start to recede or increase or if strong currents unexpectedly develop, a tsunami has arrived. It is imperative to get off beaches and move away from the water's edge to higher ground immediately once this behavior of the tide is observed.
There will likely be warning time if a distant event such as an earthquake in the Puerto Rican Trench is forecast to produce a tsunami in the Gulf of Maine. Once the tsunami waves reach the Gulf of Maine, keep distant from the water's edge. It is important to remember that during a tsunami event in the Gulf of Maine, water levels will fluctuate rapidly and chaotically and surge size can vary extensively long local areas in Maine. Do not approach the water's edge until emergency officials or the National Weather Service indicate that the dangerous conditions have subsided.