The storm that devastated Myanmar (previously called Burma) was in fact a tropical cyclone. A tropical cyclone can be a tropical depression, tropical storm, or hurricane. But in other parts of the world, the same storm systems are referred to by different names, including typhoon, willy-nilly, or just simply "cyclone". Whatever the terminology, these names all apply to a warm-core cyclonic storm that, in the northern hemisphere, has winds spiraling into the center in a counter-clockwise manner, and that, in the southern hemisphere, has winds spiraling into the center in a clockwise manner. Other than the difference in spiraling wind direction, the storms look similar in satellite and radar imagery.

The "cyclone" that devastated Myanmar was named "Nargis", and was classified as a Category 3 tropical cyclone on the Saffir-Simpson scale. Category 3 tropical cyclones have winds of 111-130 mph . These storms often produce storm surges 9-12 ft above normal, cause some structural damage to small residences and utility buildings, and destroy mobile homes and poorly constructed buildings. Flooding near the coast destroys smaller structures with larger structures damaged by battering from floating debris. Flooding is frequently the primary cause of death when tropical cyclones make landfall, and terrain continuously lower than 5 ft above mean sea level may be flooded inland 8 miles or more. Such was the case in Myanmar, where a vast area of river delta (associated with Myanmar's longest river, the Irrawaddy) lies very close to sea level, and is very densely populated. The latest reports indicate that over 90% of the deaths occurred in the Irrawaddy delta area.

Flooding from tropical cyclones is in no way related to flooding caused by a tsunami. A tsunami is a series of waves created when a body of water (such as an ocean) is rapidly displaced. Most tsunamis are caused by earthquakes. Other causes include mass movements above or below water, volcanic eruptions, underwater explosions, landslides, and large asteroid impacts. The devastating effects of a tsunami are due to the immense volumes of water in motion, and the energy generated by the motion of the water.