tsunami vs storm surge

[cancunkid]

Okay after having seen video of the tsunami last December and video of the storm surge of Katrina I was struck by how similar they looked. First I was shocked in December because I always assumed a tsunami would be a huge looming looking thing like on a movie poster it wasn't until after watching the video a couple of times that I figured it is the wall of water behind the original wave that causes damage. Logistically are there more similarities (displaced bulge of water) than differences in the two disasters?

[SouthFloridawx]

The surge was much more incredible than anyone expected. Here is the NHC definition of Cat 4 and 5 Hurricanes


Category Four Hurricane:
Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally 13-18 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). Hurricane Charley of 2004 was a Category Four hurricane made landfall in Charlotte County, Florida with winds of 150 mph. Hurricane Dennis of 2005 struck the island of Cuba as a Category Four hurricane.

Category Five Hurricane:
Winds greater than 155 mph (135 kt or 249 km/hr). Storm surge generally greater than 18 ft above normal. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. Complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5-10 miles (8-16 km) of the shoreline may be required. Only 3 Category Five Hurricanes have made landfall in the United States since records began: The Labor Day Hurricane of 1935, Hurricane Camille (1969), and Hurricane Andrew in August, 1992. The 1935 Labor Day Hurricane struck the Florida Keys with a minimum pressure of 892 mb--the lowest pressure ever observed in the United States. Hurricane Camille struck the Mississippi Gulf Coast causing a 25-foot storm surge, which inundated Pass Christian. Hurricane Andrew of 1992 made landfall over southern Miami-Dade County, Florida causing 26.5 billion dollars in losses--the costliest hurricane on record. In addition, Hurricane Gilbert of 1988 was a Category Five hurricane at peak intensity and is the strongest Atlantic tropical cyclone on record with a minimum pressure of 888 mb.

[Astro_man92]

I'd say that storm surge on the scale of Katrina's (I think 30+) is about the same as the Tsunami that hit Indonisia last year. I think I heard that the Tsunami only went is 2 miles inland (please correct me if i'm wrong) but i also heard that Katrina's Storm Surge went over 6 miles inland and I think some rivers had broke there banks 6 miles in either direction. So actually I think that Katrina's Storm Surge was worse.

[Canelaw99]

Bear in mind also that the areas where Katrina had some of the worst surge are actually below sea level. So, in the NHC descriptions, if terrain 10 ft. above sea level would flood, that guarantees anything less, especially below sea level, would flood. I agree though that it did seem worse than what some had predicted, but all knew this was the worst case scenario for the SE LA area.

[Astro_man92]

The surge was much more incredible than anyone expected. Here is the NHC definition of Cat 4 and 5 Hurricanes


Category Four Hurricane:
Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally 13-18 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). Hurricane Charley of 2004 was a Category Four hurricane made landfall in Charlotte County, Florida with winds of 150 mph. Hurricane Dennis of 2005 struck the island of Cuba as a Category Four hurricane.

Category Five Hurricane:
Winds greater than 155 mph (135 kt or 249 km/hr). Storm surge generally greater than 18 ft above normal. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. Complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5-10 miles (8-16 km) of the shoreline may be required. Only 3 Category Five Hurricanes have made landfall in the United States since records began: The Labor Day Hurricane of 1935, Hurricane Camille (1969), and Hurricane Andrew in August, 1992. The 1935 Labor Day Hurricane struck the Florida Keys with a minimum pressure of 892 mb--the lowest pressure ever observed in the United States. Hurricane Camille struck the Mississippi Gulf Coast causing a 25-foot storm surge, which inundated Pass Christian. Hurricane Andrew of 1992 made landfall over southern Miami-Dade County, Florida causing 26.5 billion dollars in losses--the costliest hurricane on record. In addition, Hurricane Gilbert of 1988 was a Category Five hurricane at peak intensity and is the strongest Atlantic tropical cyclone on record with a minimum pressure of 888 mb.

I bet the reason why the storm surge was so high was because it was still winding down from Katrina's Peak intensity and the fact that the area that it had stuck was 6 or more feet below sea level

[MKT2005]

Okay after having seen video of the tsunami last December and video of the storm surge of Katrina I was struck by how similar they looked. First I was shocked in December because I always assumed a tsunami would be a huge looming looking thing like on a movie poster it wasn't until after watching the video a couple of times that I figured it is the wall of water behind the original wave that causes damage. Logistically are there more similarities (displaced bulge of water) than differences in the two disasters?

Actually some Tsunami are giant walls of water, but most aren't. However there are records of Tsunami thousands of feet in hight.

[nolabelplez]

Our local weather man was upset that someone used this analogy. He said the most important thing was that this DID NOT come without warning.
Tsunami victims were there, because they had no idea something was coming. We knew this was coming, and people decided to stay behind (or felt they had no choice or means to leave). It wouldn't have helped the property loss, but lives could have been saved here.

[MKT2005]

Our local weather man was upset that someone used this analogy. He said the most important thing was that this DID NOT come without warning.
Tsunami victims were there, because they had no idea something was coming. We knew this was coming, and people decided to stay behind (or felt they had no choice or means to leave). It wouldn't have helped the property loss, but lives could have been saved here.

Actually a Tsunami does give warning before it hits, which is why a tribe evacuated before it hits, it just doesn't give much warning.

[dwg71]

Okay after having seen video of the tsunami last December and video of the storm surge of Katrina I was struck by how similar they looked. First I was shocked in December because I always assumed a tsunami would be a huge looming looking thing like on a movie poster it wasn't until after watching the video a couple of times that I figured it is the wall of water behind the original wave that causes damage. Logistically are there more similarities (displaced bulge of water) than differences in the two disasters?

Actually some Tsunami are giant walls of water, but most aren't. However there are records of Tsunami thousands of feet in hight.

That is factually incorrect, Tsunamis are about 10-30FT in height. Due to other influences isolated wave heights could reach up to 100FT. Thousands of feet could not happen.

[MKT2005]

Okay after having seen video of the tsunami last December and video of the storm surge of Katrina I was struck by how similar they looked. First I was shocked in December because I always assumed a tsunami would be a huge looming looking thing like on a movie poster it wasn't until after watching the video a couple of times that I figured it is the wall of water behind the original wave that causes damage. Logistically are there more similarities (displaced bulge of water) than differences in the two disasters?

Actually some Tsunami are giant walls of water, but most aren't. However there are records of Tsunami thousands of feet in hight.

That is factually incorrect, Tsunamis are about 10-30FT in height. Due to other influences isolated wave heights could reach up to 100FT. Thousands of feet could not happen.

You are WRONG, look up the largest Tsunami in the last 100 years, its hight measured more than 1500 feet. Tsunami created from meteors or rocks/ice falling into the oceans measure thousands of feet in hight.

On July 7th 1958 a Tsunami struck Alaska that measured more than 1638 feet in hight.

[dwg71]

That was caused by a landslide and I was aware of that wave, actually saw a report from a survivor. I was speaking of only typical tsunamis that earthquakes and volcanica eruptions. I failed to include landslides, but 1600ft is not "thousands" of feet...

[AlabamaDave]

I bet the reason why the storm surge was so high was because it was still winding down from Katrina's Peak intensity and the fact that the area that it had stuck was 6 or more feet below sea level

I think you are correct on the reason for the exceedingly high storm surge (winding down from Cat-5 so it actually brought in a Cat-5 surge), but the highest surge did not strike areas below sea level. The areas below sea level are in New Orleans, which did not receive the highest surge. The flooding in New Orleans is due to levee failures as a result of lesser surge. The highest surge was along the Mississippi coastline, which is not below sea level.

[MKT2005]

That was caused by a landslide and I was aware of that wave, actually saw a report from a survivor. I was speaking of only typical tsunamis that earthquakes and volcanica eruptions. I failed to include landslides, but 1600ft is not "thousands" of feet...

There is geological evidence of Tsunami which measure more than 2000 feet in height happening from rock/ice collapse into the ocean. Remember only a small amount of ice and rock broke off into the ocean to creat that giant wave in Alaska. I know these events are, but they do happen, and no doubt one day one of these giant tsunami will strike densly populated area.

[Astro_man92]

That was caused by a landslide and I was aware of that wave, actually saw a report from a survivor. I was speaking of only typical tsunamis that earthquakes and volcanica eruptions. I failed to include landslides, but 1600ft is not "thousands" of feet...

There is geological evidence of Tsunami which measure more than 2000 feet in height happening from rock/ice collapse into the ocean. Remember only a small amount of ice and rock broke off into the ocean to creat that giant wave in Alaska. I know these events are, but they do happen, and no doubt one day one of these giant tsunami will strike densly populated area.

I heard that it wasn't a block of ice it was praticly a tall hills face that slid into the water creating the tsunami

[cancunkid]

Okay I have a follow up question about surge. When an area replenishes a beach over and over and over for lets say 35 years would the sea floor bed possibly be shallower further out? Making surge worse with each beach replenishing program? I know this is highly unlikely due to the vast area of the ocean but with all the hurricanes in the past 2 years hitting the same areas over and over I have to wonder if matters could be made worse.

[senorpepr]

Our local weather man was upset that someone used this analogy. He said the most important thing was that this DID NOT come without warning.
Tsunami victims were there, because they had no idea something was coming. We knew this was coming, and people decided to stay behind (or felt they had no choice or means to leave). It wouldn't have helped the property loss, but lives could have been saved here.

I would tend to agree with the weather man. I am a little bothered with the comparison between this and the tsunami this past winter. Don't get me wrong, Katrina was a very tragic event, but we must keep in mind that there was little warning with the tsunami. In addition, in many of the locations it impacted, the word of an approaching tsunami would be hard to pass around. Whereas with Katrina, it impacted a modernized area. The folks impacted by Katrina knew she was coming. Matter of fact, they had roughly 30 hours from the time the hurricane warnings were posted. The idea of comparing Katrina and the December tsunami is completely mismatched.

[Derecho]

Tsunamis are about 10-30FT in height.

The tsunami in Banda Aceh Indonesia was 100 feet high.

The tsunami when it hit Thailand and Sri Lanka was comparable in height to Katrina's surge in Mississippi.

However, I'd posit a 30 foot tsunami would be a bit more damaging than a 30 storm surge, due to the water rapidly cycling in and out (typically there are 3-10 waves for a tsunami, with the water completely retreating in between them) even though the storm surge would have wind waves on top of it.

[wxmann_91]

As I have posted on another thread from a LONG time ago, tsunamis are much more deadly and destructive than storm surge. (This is of course if you're comparing them and they hit the same area, a 10 ft storm surge in Bangledesh would do more damage than a 10000 ft tsunami in Antarctica .)

Tsunamis are several waves. They travel faster, and they can occur on sunny days, where there is almost no warning. Remember that only half the time a trough precedes a crest, and sometimes a crest comes without warning. I'm betting with all the wind and rain around someone who doesn't know what a hurricane or surge is will even realize something is wrong.