The Largest Tsunami Ever Recorded Resulted in Just 2 Deaths

If you've never experienced a tsunami up close, you're fortunate. But you probably know that these colossal waves can cause incredible destruction. Tsunamis are measurable events, raising the obvious question: What was the largest tsunami ever recorded?

Here, we will examine the massive tsunami that hit Lituya Bay, Alaska, which holds the record as the largest tsunami in history. Additionally, we will explore other notable tsunamis and dive into the science behind these giant waves.

What Is a Tsunami?

A tsunami is a colossal wave, or more precisely, a series of massive waves, triggered by the sudden movement of water. This usually happens due to an abrupt geological event, such as an earthquake or volcanic eruption.

Tsunamis can also occur due to landslides or the breaking off of glaciers, where enough water is displaced to create waves that are much longer than typical ocean waves. The term comes from Japanese, where it directly translates to 'harbor wave.'

Are Tsunami Waves the Same as Tidal Waves?

Although cinematic depictions often show tsunamis as towering, crashing waves, in reality, they frequently appear as a rapidly rising tide. This is why they are sometimes referred to as 'tidal waves.'

However, this terminology is technically incorrect, as tides are driven by the moon's gravitational pull. Tsunamis, on the other hand, do not rely on the moon's gravity; they are simply caused by the displacement of water. Despite this inaccuracy, the term 'tidal waves' is still commonly used.

The Largest Tsunami Ever Recorded: Lituya Bay (1,720 Feet)

On July 9, 1958, a powerful 7.8-magnitude earthquake rocked Alaska's Fairweather fault line, triggering a massive rockslide into Lituya Bay. This catastrophic event sent nearly 40 million cubic yards of rock into the water, creating the conditions for one of the most extraordinary natural disasters ever recorded.

Much like how a rock thrown into water creates a splash — and the larger the rock, the bigger the splash — the enormous landslide created a wave of unimaginable size and power, displacing water with staggering force.

This colossal wave reached an astonishing height of 1,720 feet (535 meters) above sea level, dramatically reshaping the landscape surrounding the bay. To put it in perspective, if the Empire State Building had been placed in the bay, this wave would have easily surpassed its peak.

Fortunately, there were very few people around the bay during this incident, and only three boats were impacted by the wave, resulting in two tragic fatalities. While this was a devastating event, it was far less catastrophic than other tsunamis that have struck more densely populated regions.

Bigger Than Tsunamis: The Mega-Tsunami

The Lituya Bay event qualifies as a mega-tsunami, a term used for rare incidents where a massive material fall, often rock or ice, displaces water. Landslides are typically the culprit behind these immense waves.

Why does this matter? The key difference is that such collapses tend to create waves even higher than those generated by undersea disturbances. This is likely due to the abruptness of the water's displacement.

5 More of History's Biggest Tsunamis

Although large tsunamis are infrequent, they have occurred throughout history. It wasn't until modern times that we had the tools to measure them accurately. Here are the top contenders for the highest waves in history, right after the Lituya Bay mega-tsunami.

1. Mount St. Helens Tsunami (853 Feet)

The eruption of Mount St. Helens on May 18, 1980, is well-known, but few realize it also triggered a massive mega-tsunami. When the mountain's northern flank collapsed, it created a landslide that displaced enough water to generate a huge wave.

This monumental wave soared to a height of 853 feet (260 meters), wreaking havoc and causing widespread destruction in its wake.

2. Vajont Dam Tsunami (820 Feet)

On October 9, 1963, a massive landslide crashed into the Vajont Dam in Italy, creating a colossal 820-foot (250-meter) wave. This disaster is unique in that it was partially caused by human intervention, as the dam created a deep reservoir capable of generating such a wave.

3. Icy Bay Tsunami (663 Feet)

Another mega-tsunami took place in Alaska, triggered by a massive landslide on October 17, 2015. A huge volume of rock plunged into Taan Fiord, an inlet of Icy Bay, causing a wave of unprecedented size.

The initial wave height reached around 330 feet (101 meters), but the run-up — the elevation to which the wave surged on the surrounding land — was even more impressive, at 633 feet (193 meters).

4. 1936 Lituya Bay Tsunami (490 Feet)

Lituya Bay, Alaska, has witnessed more than one giant wave. Prior to the world-record 1958 tsunami, another occurred on October 27, 1936. Though the exact cause remains unclear, an undersea landslide is suspected. This tsunami generated a wave with a run-up of 490 feet (150 meters) and an estimated height between 100 and 200 feet (30 and 76 meters).

5. Karrat Fjord Tsunami (328 Feet)

On June 17, 2007, in Greenland, a landslide triggered by melting glacial ice resulted in a massive 328-foot (100-meter) wave. This powerful wave surged through Karrat Fjord, causing destruction as far as 62 miles (100 km) away.

Most Destructive: Indian Ocean Tsunami (230,000 Fatalities)

While earlier tsunamis were ranked by the size of the waves they generated, height doesn’t always correlate with destruction. In 2004, an earthquake near Sumatra, Indonesia, triggered the most devastating tsunami in recorded history, known as the Indian Ocean tsunami.

The first wave struck the coastlines of 14 countries, from India's east coast to Myanmar's west coast, unleashing widespread devastation. As more waves followed, the total death toll reached an unimaginable 230,000 people.

While some waves reached heights of 100 feet (30 meters), the majority of the devastation and loss of life occurred in the densely populated coastal regions.