A tsunami is a giant ocean wave that comes ashore. It is caused by a submarine earthquake, underwater or coastal landslides, or volcanic eruptions. As the wave nears the continent the fast-moving water piles up on the slower-moving water near shore. As it approaches the shore, typically the water will recede from the coastline before the tsunami approaches.

The most notable tsunamis in history have made a big impact. Lituya Bay in Alaska has been a hot spot of tsunami activity. They had a 394 ft wave in 1853, a 490ft wave in 1936, and the biggest tsunami, in recorded history, a 1720ft wave in 1958. 

Big waves destroy lives and cause billions in damage. The 2004 quake in the Indian Ocean hit Sumatra, Indonesia causing ten billion dollars in damage and killing $300,000 in damages. The second most deadly tsunami in history is a tie between the tsunami that hit Portugal, Morocco, Ireland, and the UK in 1755 and the wave that hit Crete and Santorini in 1645. Both of these events killed about 100,000 people respectively.

Even though oceanic areas around the Pacific Ring of Fire are at great threat due to seismic activity, tsunamis don't just happen on the ocean. When Mount St. Helens erupted in 1980, it caused an 820ft wave in Spirit Lake. 

The oceans are monitored by buoys. Tsunami.gov monitors the alerts and you can find your specific alert station there. Weather.gov/tsunamiready is a program that can prepare your community to be more adept at handling a tsunami event. 

You can personally prepare by knowing the hazard zones in your area. Learn multiple routes to high ground and practice driving those routes. Know where you are going to go if you have a medical emergency during a tsunami. Learn where to monitor alerts and have a portable NOAA weather readio to monitor activity.radio