# Does a hurricane's storm surge look like a tsunami? A wall of water? **URL:** \ **Category:** Factual Questions\ **Created:** [July 12, 2005, 2:33am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109 "2005-07-12T02:33:52Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [July 12, 2005, 2:33am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/1 "2005-07-12T02:33:52Z")
I just finished reading a thriller called _Presidential Deal_ by Les Standiford, and in it, he has the hero and heroine stranded on one of those tiny nameless Bahamian cays during a hurricane, and he has the hurricane’s storm surge come up over the island like a tsunami, a fast-moving wall of water that sweeps away everything in its path on the island, except for the big blocks of stone in the abandoned quarry where the hero and heroine have taken refuge (as for why there’s an abandoned quarry on a tiny nameless Bahamian cay, I have no idea). And the tiny nameless Bahamian cay was described as being barely 20 feet above sea level, so we’re talking at least a 20 to 30-foot high wave. Anyway… My understanding has always been that the storm surge is just a fast-moving tidal flow of incoming sea water, a “bulge” of water, a really high tide that comes in in a really big hurry, not that it’s a tsunami-like devastating “wave” that sweeps things away. Anybody out there ever actually witnessed a storm surge? ---
**Author:** ![Snowboarder\_Bo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowboarder_bo/32/229_2.png) [@Snowboarder\_Bo](https://boards.straightdope.com/u/Snowboarder_Bo)\ **Post date:** [July 12, 2005, 3:39am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/2 "2005-07-12T03:39:52Z")
I have. I grew up in South Florida and went thru umpty-ump hurricanes. You are correct, a hurricane storm surge is a significant increase in the tidal swells, and can cause flooding inland, but is NOT like a tsunami. more info at [http://hurricanes.noaa.gov/prepare/surge.htm](http://hurricanes.noaa.gov/prepare/surge.htm) ---
**Author:** ![trupa](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@trupa](https://boards.straightdope.com/u/trupa)\ **Post date:** [July 12, 2005, 3:48am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/3 "2005-07-12T03:48:01Z")
> [@Snowboarder Bo](#): > > I have. I grew up in South Florida and went thru umpty-ump hurricanes. You are correct, a hurricane storm surge is a significant increase in the tidal swells, and can cause flooding inland, but is NOT like a tsunami. > > more info at [http://hurricanes.noaa.gov/prepare/surge.htm](http://hurricanes.noaa.gov/prepare/surge.htm) that is a cool animation on that site, plus some eye-popping maps of Manhattan in various category storm surges. ---
**Author:** ![Carnac\_the\_Magnificent](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Carnac\_the\_Magnificent](https://boards.straightdope.com/u/Carnac_the_Magnificent)\ **Post date:** [July 12, 2005, 1:25pm UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/4 "2005-07-12T13:25:59Z")
> [@Snowboarder Bo](#): > > I have. I grew up in South Florida and went thru umpty-ump hurricanes. You are correct, a hurricane storm surge is a significant increase in the tidal swells, and can cause flooding inland, but is NOT like a tsunami. > > more info at [http://hurricanes.noaa.gov/prepare/surge.htm](http://hurricanes.noaa.gov/prepare/surge.htm) Remember the lessons of Christmas 2004: A tsunami doesn’t always look like a tsunami. Not 100 percent on the terms, but I think the surge more closely approximates a tidal “bore.” IOW, there’s a gradual rise in the entire sea–sometimes up to 30 feet–with fairly big waves sometimes riding atop this elevated sea level. Make sense? ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [July 12, 2005, 2:21pm UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/5 "2005-07-12T14:21:47Z")
Yeah, it does, thanks. I’m familiar with the concept of a tidal bore, although I’ve never personally seen one. But I don’t think this is it: > [@](#): > > …Linda clutched his arm. “What is _that_?” she cried above the thundering wind… > > He blinked against the needlelike rain and strained to see in the ever-dimming light…Finally he saw it: a thin, continuous band of white, dividing the horizon where sea met sky. In the few seconds that he watched, the band seemed to widen, to grow a pale fraction and then another… > > “Let’s go,” he said, glancing over his shoulder at the ever-widening, ever-advancing band of white… > > …“The storm surge,” he shouted as he ran after her. “That fucking wall of water I was talking about.” So they clamber up the hill towards the quarry, and at the last minute he looks back: > [@](#): > > …The grinding and roaring at his back had grown, the ground shuddering…The light also racing the wall of water at their backs, not wanting to be swallowed… And just as he makes it into his hidey-hole: > [@](#): > > …the sound behind a frothing explosion of snapping timber and grinding rocks, a monster mouth gnashing at his heels. And then when they come out: > [@](#): > > Twelve hours before, they’d run for their lives up a forested trail. Now they stared down a slope that had been blasted clean, defoliated as if by a bomb blast…Behind them, where there had been the hollow of a deep vine-choked quarry site, there was now a lake, maybe two hundred feet across, filled to the brim with seawater left behind by the big wave… And there are stranded fish flopping about… Doesn’t sound like a tidal bore, even. Sounds like a tsunami. A reely, reely big one, too. ---
**Author:** ![Bambi\_Hassenpfeffer](https://avatars.discourse-cdn.com/v4/letter/b/bbe5ce/32.png) [@Bambi\_Hassenpfeffer](https://boards.straightdope.com/u/Bambi_Hassenpfeffer)\ **Post date:** [July 13, 2005, 1:24am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/6 "2005-07-13T01:24:49Z")
> [@Duck Duck Goose](#): > > Doesn’t sound like a tidal bore, even. Sounds like a tsunami. A reely, reely big one, too. Yeah. The storm surge related to a hurricane is nothing like that. As a hurricane moves across the ocean, its winds and pressure effects act to build up an area of sea water that is higher than mean sea level. It’s basically a hill in the ocean that moves at roughly the same speed as the hurricane, AFAIK. As the hurricane approaches land, it carries this hill along with it onto land. Hurricanes move fairly slowly, and the buildup of the water along the coast is (relatively) gradual, so it’s nothing that you would have to run from, and certainly nothing like in that story. BTW, last year when (then-)TS Frances blew through here, she brought a storm surge with her. You can see the results [here](http://media.tbo.com/tbo/flash/hurricanefrances/photogalleries/tampaflooding/), in this gallery. You can see from the photographs that this was gradual, because the rising sea did not damage the trees and bushes. The only damage to the buildings was from the flooding, not any sort of violent wave activity. What happened here is that the storm pushed the water from Tampa Bay up into the Hillsborough River, which flows through downtown Tampa before emptying into the bay itself. The water level in the bay was higher than that of the river, so the river was basically dammed by the storm surge and rose over its banks, adding even more water to the 4 - 8 ft surge which Frances was bringing ashore. In addition, you can see in some of the pictures that there are waves washing over the bridges – that’s because the wave activity on top of this hill of water stays basically the same as it does on a normal sea. The waves are just forming higher than usual. The night before was really something. Thanks to the winds and the shape of the bay in certain areas, you could see the seafloor for about 100 yards out along Bayshore Blvd, which is built along a sea wall. Ordinarily, there’s really no beach there at all, much less one 300 ft wide. But again, that was a gradual recess of the waters and a gradual return overnight and into the next day. Oh, and from my understanding of tidal bores, it’s not really anything like that either, at least around here. All the pictures of tidal bores I could find showed a little water wall moving up a river. It’s not even like a wall at all. It’s more like a tide that just keeps coming in. ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [July 13, 2005, 1:48am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/7 "2005-07-13T01:48:13Z")
> [@](#): > > Finally he saw it: a thin, continuous band of white, dividing the horizon where sea met sky. In the few seconds that he watched, the band seemed to widen, to grow a pale fraction and then another… How did he see _anything_ through the tons of rain in the air, much less the wave caps that were being blown around by the wind? Visibility in the one hurricane that I weathered was at one quarter mile or less (admittedly, I was miles inland.) A storm surge is made of water piled up by the winds that blow towards the low pressure of the eye. It has a gradual slope, not the steep face of a breaker or rogue wave. Of course, there will be a lot of heavy seas atop the storm tide. ---
**Author:** ![Bambi\_Hassenpfeffer](https://avatars.discourse-cdn.com/v4/letter/b/bbe5ce/32.png) [@Bambi\_Hassenpfeffer](https://boards.straightdope.com/u/Bambi_Hassenpfeffer)\ **Post date:** [July 13, 2005, 2:17am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/8 "2005-07-13T02:17:09Z")
> [@Duck Duck Goose](#): > > (as for why there’s an abandoned quarry on a tiny nameless Bahamian cay, I have no idea). What are they quarrying? Ancient coral? > [@Duck Duck Goose](#): > > And the tiny nameless Bahamian cay was described as being barely 20 feet above sea level, so we’re talking at least a 20 to 30-foot high wave. Also, a storm surge of 30 feet would be the result of an off-the-chart category 5 hurricane. Category 5s start at winds of 155 mph and storm surge greater than 18 feet. In a storm with a 30 foot surge, the water would be among your final concerns. The greatest immediate concern would be the 200 mph winds turning everything outside into a deadly missile. > [@Duck Duck Goose](#): > > Anybody out there ever actually witnessed a storm surge? Yes, and I have pictures. If you didn’t know the regular water level in the area, you’d not even notice that it’s happening until it starts lapping at the coastal roadbeds. It’s not a wave; it’s more like a tidal inflow. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [July 13, 2005, 2:52am UTC](https://boards.straightdope.com/t/does-a-hurricanes-storm-surge-look-like-a-tsunami-a-wall-of-water/312109/9 "2005-07-13T02:52:08Z")
> [@Bambi Hassenpfeffer](#): > > What are they quarrying? Ancient coral? Apparently so. It certainly isn’t a granite quarry… 😃 > [@](#): > > _If you didn’t know the regular water level in the area, you’d not even notice that it’s happening until it starts lapping at the coastal roadbeds. It’s not a wave; it’s more like a tidal inflow._ Yeah, that’s pretty much what I thought. Nice to have it officially confirmed, though. Thanks, all, for the input.