Many people acted heroically in the aftermath of Hurricane Katrina. The Coast Guard, for instance, rescued some 34,000 people in New Orleans alone, and many ordinary citizens commandeered boats, offered food and shelter, and did whatever else they could to help their neighbors.
Tidal waves, or tides, are a predictable, com-mon occurrence along coastal communities, generated by forces beyond Earthâthe gravitational pull of the sun and moon. However, tsunamis are not predictable. They are often generated by earth-quakes, volcanic activity, and slope failure.idal waves, or tides, are a predictable, com-mon occurrence along coastal communities, generated by forces beyond Earthâthe gravitational pull of the sun and moon. However, tsunamis are not predictable. They are often generated by earth-quakes, volcanic activity, and slope failure.
Different kinds of events can produce a tsunami. The least probable, but still possible, cause is the impact of an asteroid or a meteorite in the sea, while the more frequent causes are underwater disturbances: a volcanic collapse, a landslide or an earthquake.