The South Pacific Applied Geoscience Commission says a preliminary study of Cyclone Heta shows that a number of factors coincided when it struck Niue.
Its acting director, Russell Howorth, says the sea surge was maximised as the cyclone passed at high tide, winds onshore acted to drive water onshore and the coast line was parallel to incoming waves.
"The impact of the storm surge on Niue clearly was dramatic because of particular circumstances that prevailed at the time. The remarkable thing is that the water level was raised to some 40 or more meters above normal. We're talking numbers now that would characteristically occur of tsunamis. An unusual aspect of it was that it impacted on many countries. We usually find that cyclones do impact up to 3 or 4 island countries, and in this case there was severe damage recorded to at least 5 countries we're aware of."
