Weather Whisperer

Surf’s Up—The Two East Coast Tsunamis

Evelyn Browing Garriss and James J. Garriss

This year, on April 11 and June 13, the East Coast was slammed with tsunamis that almost nobody noticed.

NOAA researchers doing tsunami research. Source NOAA

On June 13 a few spear fishermen and three people on a jetty were pulled out to sea in a wild ride off the coast of New Jersey. Brian Coen, one of the fishermen described a six foot wave that retreated out to sea, dragging his boat and partners out beyond a breakwater. Then the water rushed back. Brian managed to maneuver his boat to safety and those caught in the tide were saved.

No one even noticed the April tsunami but automatic buoys near New Jersey recorded the high wave. Scientists from the U.S. Geological Survey's Woods Hole Field Station, discovered the event when they checked the data. Now they are studying both tsunamis.

It seems that the tsunamis may have had different causes. As noted in the Old Farmer’s Almanac’s last weather blog, there was a series of storms, called a derecho that swept from Iowa to New Jersey on June 12/13. The nickname for derecho is “Blowdown” because they sometimes blast straight down, flattening large areas of trees. Scientists now suspect that when the derecho swept out to sea, it blasted the ocean. If the strength, speed and timing of storm winds is just right, a normal storm surge grows into a tsunami. Buoys from Massachusetts to North Carolina recorded the wave, indicating it was a meteotsunami, a tsunami caused by a storm.

Landslides in underwater canyons off the East Coast can cause tsunamis. Source – USGS

There was no bad weather on April 11. The buoys show a tsunami hit in a much more limited area, mostly coastal New Jersey. This limited type of tsunami is more typical of nearby underwater landslides. Scientists think there may have been a landslide in Hudson Canyon, which slices into the edge of the continental shelf about 100 miles off the coast of New Jersey and Long Island.

NOAA plans to send their survey ship Okeanos Explorer, which will use sonar  to explore the ocean floor to see if there are traces of a landslide.

Almost nobody noticed the two East Coast tsunamis this year. Now scientists are learning from them how to understand the ocean and make living near the East Coast beaches safer.


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The winds from the derecho

The winds from the derecho would have been blowing OFF was the tsunami the water rushing back toward shore after it was pushed out to sea by the gust front?