Tsunamis Can Actually Be Created By Weather

People run as a meteotsunami crashes shore on Captiva
Island, Florida on Friday

A lot of us have read in horror about the tsunami that swept through an Indonesian seaside town over the weekend during a rock concern on the beach. The disaster killed nearly 400 people. 

Unlike the overwhelming majority of tsunamis, this one wasn't created by an earthquake. Instead, it looks like a volcano erupted, triggering a huge landslide on one side of the volcano, which then plunged into the sea.

This in turn created the huge waves that caused so much death and destruction and sorrow this weekend in Indonesia.

As noted, almost all tsunamis are created by earthquakes. The earth thrusts during a a big tremor, and that lifts a vast amount of water. When this mass of water nears shore, it encounters shallower water, so it builds up into immense waves that create these big disasters.

Weather can also create tsunamis of sorts, but luckily they're almost never as bad as the ones induced by earthquakes. Still they can cause a lot of damage.

On Friday, one such tsunami hit Captiva and Sanibel islands  Florida. These are called meteotsunamis.

I'll let NOAA explain what they are:

"Meteotsunamis are large wave that scientists are just beginning to better understand. Unlike tsunamis triggered by seismic activity, meteotsunamis are driven by air pressure differences often associated with fast-moving weather events such as severe thunderstorms, squalls and other storm fronts. The storm generates a wave that moves towards the shore, and is amplified by a shallow continental shelf, bay or other coastal feature."

That's what happened Friday at Captiva Island, Florida. A powerful squall line associated with that strong storm slammed into the western shore of the Sunshine State Friday. The squall line surged water ahead of it, and when the wave encountered shallower water off Captiva Island, the wave piled up, then crashed ashore.

The Captiva Island meteotsunami caused damage, but it wasn't the worst one ever.  Says NOAA: "Meteotsunamis have been observed to reach heights of six feet or more. They occur in many places around the world, including the Great Lakes, Gulf of Mexico, Atlantic Coast and the Mediterranean and Adriatic Seas."

Even where they do sometimes occur, meteotsunamis do surprise people.   A squall line on May 15 caused an unusually severe outbreak of tornadoes and high winds in southern New England and the Mid-Atlantic states.

The tornadoes of course dominated the news, but the pressure changes associated with the squall line were intense enough to cause a meteo-tsunami along the coast from Connecticut to Maryland. This wasn't a damaging tsunami, as waves never got above 10 inches over normal high tides. But it was an unusual event, proving the atmosphere can influence the vast oceans as well.

Florida seems particularly prone to meteotsunmis. Perhaps one of the worst meteotsuamis in U.S history hit during the massive "Storm Of The Century" blizzard of March, 1993. As areas from Georgia to Maine were buried in up to three feet of snow, a squall line associated with the storm slammed into western Florida, causing a destructive meteotsunami.

A year earlier, a meteotsunami injured 75 people in Daytona Beach, Florida. Other ones hit in 2014 and 2016.

Most meteotsunamis aren't this destructive.  The vast majority are too small for most people to notice, but are picked up by tidal and water level guages.

There's another related phenomenon called a seiche. That's when strong winds, often shifting, push water in a lake onto one shore, then the water sloshes back to the other side, much like water can slosh in a bathtub if you move around too much.

Seiches, like meteotsunamis, can easily cause shoreline flooding.

Here's video of the meteotsunami in Florida on Friday. As you can see, they an be quite dramatic:

Northeast Severe Storm/Tornado Outbreak Was Almost Oklahoma Style

Ominous storm clouds gather over New York City on Tuesday. The storms
caused damage in New York City, and especially further north
in Westchester County.

On Tuesday, we had the spectacle of seeing classic Oklahoma style supercell thunderstorms strike places that aren't exactly tornado alley - like New York, Connecticut and Pennsylvania.

This really was one of the more spectacular severe weather outbreaks I've seen in the Northeast in recent years. Some videos of the wild weather are at the bottom of this post.

So far, I've heard one or two reports of confirmed tornadoes Tuesday in the Northeast, but I believe that number will rise as National Weather Service investigators pick through areas of particularly heavy damage to see if the destruction was caused by tornadoes, or straight-line winds.

Though most of the damage will end up being from intense gusts, a few places will surely had tornadoes.

There were certainly several supercell thunderstorms in which radar indicated possible tornadoes. At least four deaths have been reported from these big storms, all from trees falling on occupied cars.

A flash flood emergency was declared in Frederick, Maryland (a lovely city where I have relatives). It's got a great downtown with beautiful old buildings, and, sadly, that downtown was definitely affected by the flooding.

The storms were strong enough to create something called a meteotsunami along parts of the East Coast. Tsunamis - often giant surges of water invading coastlines are caused by earthquakes. Meteotsunamis are created by storms and air pressure changes.

It's not as if meteotsunamis are super destructive - they usually just cause rather modest waves and flooding along shorelines, and that was the case Tuesday. In places like coastal New Jersey, wind patterns and abrupt air pressure changes associated with the band of severe storms caused some minor surges and flooding.

Some of the storm damage reports are, again, pretty incredible considering the location. Winds gusted to 78 mph in Beacon, New York. Several roofs were damaged or at least partly blown off buildings in Newburgh, New York. A roof blew off a Dunkin Donuts in Westchester County, New York and another roof blew off a nursery school in Passaic, New Jersey.

Storms sent this large tree crashing through a house in Cheshire, CT

The storms blasted into New York City, turning the evening commute into a nightmare because so many train tracks were blocked by fallen trees.

 At 133rd Street and Broadway in Manhattan, scaffolding and construction debris, including corrugated metal blew down, injuring several people.

Hail the size of tennis balls hit some towns in the Hudson Valley and southwestern New England.

In Granby, Connecticut, the hail was big enough to smash house windows and cars traveling on the town's streets and nearby highways.

Here in Vermont, we dodged another bullet. It looks like there was some strong-ish thunderstorms along the Massachusetts border but there was no major damage.

It had been getting dry in Vermont, and the rains that came Tuesday were heavier than I had expected, which is a good thing. While some places in the state missed out, other towns got a good half inch of rain, which was nice.

Severe thunderstorms are over in the Northeast, but some heavy rain and the risk of flooding is still going to be a problem in parts of the Mid-Atlantic states, especially in already soggy places like Maryland, Delaware and New Jersey.

Here's a tornado-warned storm slamming Saugerties, New York:



Lots of storm damage along the Merritt Parkway in Connecticut. Note the cars stuck on the highway between fallen trees.



Definite rotation Tuesday in Barkhamsted, Connecticut.  Judging from the video, I don't think this one touched down. At least when this video was shot:



Downtown flooded as torrential rain and hail falls in Frederick Maryland:

"Meteotsunami" Hits Florida: A New Weather Word Explained

The effects of a meteotsunami along the
Adriatic Sea in 2008. 

During the tornadoes and severe storms that hit Florida early Sunday, something called a "meteotsunami" hit the Gulf Coast city of Naples.

Add that to the list of isoteric meteorological terms getting batted around, like Polar Vortex or El Nino or Arctic Oscillation.

A tsunami, as most of us know, is a huge flood of waves and water caused by an undersea earthquake or landslide.

A meteotsunami, as the name suggests, is caused by a meteorological or weather situation.

An intense squall line connected to a strong storm system approached Naples from the Gulf of Mexico very early Sunday morning.

The squall line abruptly reduced the air pressure in the eastern Gulf of Mexico, which allowed water levels to rise, note Kris Mattarochia, a National Weather Service meteorologist in Miami, according to the Naples Daily News.

Very strong winds associated with the squall line also helped make water levels rise and shove that high water to the coast. (Note that the wind gusted to 85 mph in Naples when the squall line came through.

This push of high water coincided with high tide, resulting in coastal flooding in downtown Naples and surrounding areas, the Naples Daily News reported. However, the most extensive damage in and around Naples was due to the wind with the squall line.

Numerous buildings and trees were trashed by the gusts.

Meteotsunamis are more common than you'd think. Some famously came ashore in Florida during hte epic Superstorm of March, 1993. A bad one hit Daytona Beach one day in July, 1992, injuring 75 people and damaging about 100 cars.

Storm chaser Jim Edds took a series of photos showing a meteotsunami striking Panama City Beach, Florida in March, 2014. Watch:

 d David Ross, a meteorologist with the National Weather Service.

The arrival of the squall line to Southwest Florida at high tide caused flooding in downtown Naples and the damage seen in Golden Gate and other areas of the county.

At the Naples Municipal Airport, winds were recorded as strong as 85 mph.

Ross said wave height reached 7.36 feet, which was more than 5.5 feet above the predicted level for the day. Meteotsunamis occur a few times a year and are more common with systems that come across the Gulf, he said.

According to NOAA, in the United States, conditions for destructive meteotsunamis are favorable in the Gulf of Mexico, along the East Coast and in the Great Lakes. One notable meteotsunami in Florida took place in July 1992 in Daytona Beach. A 10-foot wave crashed ashore shortly before midnight, causing injuries to 75 people and damaging property and 100 cars.