Let's talk about the risk of dying from a tsunami in 2 terms -- frequency (how often does a tsunami happen?) and magnitude (when a tsunami hits land, how many people die). Tsunamis happen quite infrequently around 1 every 10 year. That's very rare, especially compared to the number of car crashes that happen every day in every city.

The second thing to consider, each time a tsunami hits, how many people die? If a tsunami hits a part of land where nobody lives (a park, wilderness etc.) then nobody would die. If a tsunami hits an area with big cities, then many people could die. However, it is unlikely that many people would die if a tsunami hit somewhere in the USA because the US has lots of science stations in the ocean that measure tsunamis. This way, if a tsunami formed and headed to the United States, they would know about it and evacuate the city where the tsunami was headed.

The 26 December 2004 tsunami killed about 150,000 people, so yes, a tsunami can kill a lot of people.

Tsunamis are generated by waves due to vertical motion of Earth's crust caused by earthquakes. The size of a tsunami depends on where it originated, the geometry of the seafloor, and the orientation of the coastline. Unlike storm waves, tsunami waves can be much bigger.

A recent tsunami in Japan, called the Tohoku Tsunami, was over 130 feet tall and traveled more than 5 miles inland. This resulted in flooding of the coastline and killed almost 16,000 people. However, the same tsunami reached the coast of California, but only caused waves to be several feet higher than normal and did not result in any lives lost.