The real difference between a storm surge and a tsunami is what causes them.

The storm surge is a push of water from the ocean caused by constant high winds in one direction from a tropical system. This occurs on the eastern side of the tropical storm or hurricane as this is the region with strong constant onshore winds. So as the storm approaches land, the water gets pushed unto the shore.

On the other hand, a tsunami is caused by an earthquake. If a quake happens in open ocean, the sharp shift in the Earth's plates causes a ripple to start in the water. Similar to a drop of water in a pool. This ripple then turns into a large wave that spreads out in all directions of the epicenter. As this wave approaches land, it gets lifted higher due to the rising of the continental shelf as you get to a coastline. Then the water gets pushed ashore in a similar fashion as a storm surge.

Both can have devistating effects on the land in a very short period of time.

~Meteorologist Keith Monday~