How Far Inland Can A Tsunami Travel On The East Coast USA?

How far inland can a tsunami travel? That’s a question you may be wondering, especially if you live near the coast. Please read through all the caveats I discuss below before checking out the maps. There’s not one answer. Instead, there are lots of “it depends”.

EAST COAST TERRAIN ELEVATION MAPS SHOWN BELOW

A while ago, I wrote an article titled “300 Foot Tsunami And East Coast Destruction” (linked below) regarding the possibility of ‘La Palma’ or ‘El Hierro’ of the Canary Islands partially collapsing into the Eastern Atlantic following a major volcanic eruption there.

This event would likely lead to a mega tsunami that travels across the Atlantic and devastates the East Coast of the United States.

Opinions vary regarding the height of the tsunami, ranging from 60 feet to 300 feet and even higher as it rolls up the East Coast of the United States and elsewhere.

However, first, please (if you don’t already have one), obtain a NOAA weather alert radio. It could save your life. Get automatically notified if a tsunami is coming.

Practical first step: If you live, work, vacation, or have family near the coast, a NOAA Weather Alert Radio is one of the simplest preparedness items to keep at home. It can wake you up for official alerts while your phone is charging, muted, offline, or in another room.

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→ Midland WR120B (My personal choice)

Canary Islands – La Palma – Cumbre Vieja Mega-Tsunami?

UPDATE: I first published this article in 2013. Eight years later, in 2021, a swarm of earthquakes rattled the Canary Islands – sparking fears of a volcanic eruption. I recalled posting the following East Coast Terrain Elevation Maps to provide some context for a “what if” scenario of a mega-tsunami, such as a tsunami initiated by a major submarine landslide at the Canary Islands, for example.

There have been fears that an eruption could cause a mega-tsunami. Steven Ward first explained this theory in research from the Institute of Geophysics and Planetary Physics at the University of California, Santa Cruz, California, two decades ago.

image via ZeroHedge via StanDeyo

Image source: Cumbre Vieja Volcano — Potential collapse and tsunami at La Palma, Canary Islands, Steven N. Ward.
(height in meters)

Evolution of the La Palma landslide tsunami from 2 minutes (upper left) to 9 hours (lower right).

Red and blue contours represent elevated and depressed regions of the ocean, respectively, and the yellow dots and numbers indicate the wave height, positive or negative, in meters. Note the strong influence of dispersion in spreading out an original impulse into a long series of waves of decreasing wavelength. See also that the peak amplitudes generally do not coincide with the first wave.

Even after crossing the Atlantic, a lateral collapse of the Cumbre Vieja volcano could impose a remarkable sequence of waves of 10-25 meters in height on the shores of the Americas. (research by Steven N. Ward).

(Cumbre Vieja is a volcanic ridge on the volcanic ocean island of La Palma in the Canary Islands.)

Okay, back to the original post:

How Far Inland Can A Tsunami Go?

“IF” a 300-foot tsunami reached the East Coast, how far inland would it go?

Logically, one might reason that the tsunami will travel inland until the elevation of the land is higher than the height of the tsunami. While that might seem logical, that’s not how it works. There are variables…

Actually, the distance a tsunami will travel inland has more to do with the energy remaining as it hits the shore.

A tsunami may speed across the ocean at hundreds of miles an hour, but at a relatively small height (because the sea is DEEP).

Its speed decreases as it approaches the shoreline (because the ground beneath it is getting shallower), but its energy begins to transfer to its monstrous HEIGHT.

When the speed of the wave approaches zero, the wave breaks, releasing much of its energy, and it will not travel much further. A hypothetical monster tsunami that reaches a height of 300 feet when it rears up at the shore (or any height) will lose energy as it travels inland.

It’s all about energy. Frequency (depending on the source of the tsunami) and Amplitude (shape of ocean floor, shoreline, and up-slope factors).

It is conceivable that a given tsunami may rear up quickly (and very high) once it reaches the shore (depending on the shape of the ocean floor leading to the shore), and then ‘break’ and lose much of its energy in a relatively short distance. While another tsunami may be more compressed (in frequency) and travel a long distance inland very quickly (as seen in Japan on March 11, 2011).

There are scientifically sound reasons for concern that, at some point in time, a mega-tsunami could engulf the entire East Coast with a wave approximately 300 feet in height and sweep everything and everybody inland. The consequences of such an event are nearly unimaginable.

Tsunami Maps (East Coast Terrain)

Out of curiosity and an interest in maps, I have custom-built the following elevation maps based on high-resolution data from USGS digital elevation maps of the United States, particularly the East Coast. I have modeled several layers of elevation along the East Coast to illustrate various height scenarios of tsunamis versus geography as they travel inland.

Having said that, there are many variables and factors affecting how far a tsunami would travel inland. So if you live 20 miles inland along the Florida coast (for example) at an elevation of 50 feet, it doesn’t necessarily mean that a 300-foot tsunami (at the shore) will have enough remaining energy to travel all the way to your location.

There are instances where such a tsunami would only travel several miles inland, while in other scenarios, it may surge up a river or bay and devastate far inland.

Regardless of the factors, you may be curious to see the following elevation graphics that I layered together, which increment 75 feet all the way to 300 feet in height along the U.S. East Coast. I would guesstimate that if you live within 20 miles of the coast, you may be vulnerable to a Canary Island ‘event’. However, this is simply my own estimation.

Which American Cities Might Be Devastated by an East Coast Mega-Tsunami?

Several observations regarding a 300-foot tsunami would be the probable devastation of the following major East Coast cities… Even a 75-foot tsunami!

CITY, (Current elevation above sea level, feet)

Portland, ME (~ 50′)
Boston, MA (~ 30′)
New Haven, CT (~ 50′)
Bridgeport, CT (~ 40′)
New York City, NY (~ 20′)
Jersey City, NJ (~ 30′)
Newark, NJ (~ 50′)
Atlantic City, NJ (~ 10′)
Wilmington, DE (~ 80′)
Philadelphia, PA (~ 40′)
Virginia Beach, VA (~ 10′)
Wilmington, NC (~ 20′)
Myrtle Beach, SC (~ 20′)
Charleston, SC (~ 10′)
Savannah, GA (~ 10′)
Daytona Beach, FL (less than 10′)
West Palm Beach, FL (less than 10′)
Fort Lauderdale, FL (less than 10′)
Miami, FL (less than 10′)

There are countless cities and towns between these coastal cities. The Eastern Seaboard of the United States includes some of the largest metropolitan areas in the country. Over one-third of the country’s population (more than 100 million people) lives along the East Coast. Evacuation would be virtually impossible for most (except for the astute who act quickly) due to only hours’ notice, probable doubt, and the subsequent immediate gridlock that would follow.

ELEVATION MAPS

THE MAPS BELOW SIMPLY SHOW ELEVATION.

NOT the expected distance, a 300-foot tsunami (or any height) would actually travel. With that said, the maps simply provide visualization and reference in this regard.

 NOTE: An evacuation plan should include:
👉 Road Atlas Map For Each State

Maine, New Hampshire, Massachusetts, Connecticut, New York Coastal Elevation Map

Chesapeake Bay & North Carolina Coastal Elevation Map

North and South Carolina Coastal Elevation Map

Georgia Coastal Elevation Map

Florida Coastal Elevation Map

Florida, with its very low elevation, would have particular problems with a tsunami moving in many miles inland!

[ Read: 300 Foot Tsunami And East Coast Destruction ]