What Are Tsunamis?

Tsunamis (pronounced soo-na-mees) are often incorrectly referred to as tidal waves, but a tsunami is actually a series of waves that can travel at speeds averaging 450 - 600 miles per hour in the open ocean. As the waves approach the coast, their speed decreases and their amplitude increases. Unusual wave heights have been known to be over 100 feet high. However, waves that are only a couple of feet high can still be incredibly destructive, causing widespread devastation.

From an initial tsunami generating source area, waves travel outward in all directions, much like the ripples caused by throwing a rock into a pond. As these waves approach coastal areas, the time between successive wave crests varies from 5 to 90 minutes. The first wave is usually not the largest in the series of waves, nor is it the most significant.  Furthermore, one coastal community may experience no damaging waves while another, not that far away, may experience destructive deadly waves. Depending on a number of factors, some low-lying areas could experience severe inland inundation of water and debris of more than 1,000 feet.    



Following the 2004 tsunami in South East Asia, and the more recent one in Japan in 2011, much greater attention is been given to the risk they pose to Saint Vincent and the Grenadines. With 85% of the population living on a narrow strip below 5 metres and less than 5 km from the high water, 80% infrastructure and 90% of economic investment also on this narrow strip, a single tsunami could be devastating.