U.S. vulnerability to sea level rise

By: Dr. Jeff Masters , 4:04 PM GMT on June 23, 2009

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In the last century, sea level rose 5 - 6 inches (13 - 15 cm) more than the global average of 7 inches (18 cm) along the U.S. Mid-Atlantic and Gulf Coasts, because coastal lands there are sinking. Over 50% of the U.S. coastline is vulnerable or highly vulnerable to sea level rise, according to the Coastal Vulnerability Index (CVI) developed by the United States Geological Survey (USGS). In the U.S., relative sea level rise (the combined effects of global sea level rise plus the fact the land is sinking) is highest along the Mississippi River Delta in Louisiana, where relative sea level rises of 3.2 ft (.98 meters) have been observed during the 20th century. This is one of the highest relative sea level rises in the world. According to the NOAA Tides and Currents sea level rise interactive tool, the U.S. tide gauges that have shown the highest rates of sea level rise over the past century are at Grand Island, LA (1.8 ft rise since 1947), Galveston, TX (1.1 ft since 1957), and Chesapeake Bay, VA (0.6 feet since 1975). Alaska and some areas along the Pacific Northwest coast are at low risk of sea level rise, because the relative sea level is actually falling at present. Land in these regions is rising as it recovers from removal of the weight of the great ice sheets that covered much of North America during the last Ice Age. For example, relative sea level at Kodiak Island, Alaska has fallen by 1.1 feet since 1975, despite the fact global sea level has been increasing.


Figure 1. Twentieth century annual relative sea-level rise rates in mm/year along the U.S. coast. The higher rates for Louisiana (9.85 millimeters [mm] per year, about 3.3 ft/century) and the mid-Atlantic region (1.75 to 4.42 mm per year, 0.6 - 1.4 ft/century) are due to land subsidence. Sea level is stable or dropping relative to the land in the Pacific Northwest, as indicated by the negative values, where the land is tectonically active or rebounding upward in response to the melting of ice sheets since the last Ice Age. Image credit: Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region (data from Zervas, 2001).

U.S. Coastal Vulnerability
The Coastal Vulnerability Index (CVI) takes into account six factors:

1) The geology of the coast. Barrier islands, river deltas, and marshes are the most vulnerable to erosion and sea level rise, while steep, rocky cliff shores are the least. Sheltered bays like Galveston Bay and Tampa Bay are less vulnerable than the exposed coasts. (Note, however, that hurricane storm surges are typically higher in sheltered bays, at least for slow-moving storms).

2) How steep the land near the coast is. Gently sloping lands are the most vulnerable. In the Gulf Coast region, the slope variable has the highest risk ranking along the Louisiana coast, the Texas coast north of Corpus Christi, and the southwest Florida coast.

3) The local rate of sea level rise. The sea level is rising faster along the western Gulf of Mexico than the eastern Gulf. The highest rates of sea-level rise in the Gulf of Mexico (and in the United States) are in the Mississippi delta region (10 mm/yr, or 1 inch/2.5 years).

4) The amount of shoreline erosion going on. Most of the U.S. coast is moderately or severely eroding, and very few areas are gaining (Figure 2).

5) The mean tidal range. Shores that have a large difference between low and high tide are less likely to get a significant storm tide--the height above mean sea level of the sum of the storm surge plus the tide. For example, in a region like Maine, which has a 12 ft range between low and high tide, a storm having a 9 ft storm surge will have a storm tide below local high tide for a quarter of a tidal cycle. Shores with a very narrow tidal range (e.g., the 2 ft tidal range common along the Texas and Louisiana Gulf Coast) will get a storm tide of 8 - 10 feet with the 9 ft storm surge in the above example. Shorelines with a narrow tidal range always get high storm tides regardless of when the storm surge hits.

6) How high the waves at shore are. Obviously, shores that experience higher wave heights are at greater risk. In the Gulf of Mexico, wave energy is highest along sections of the Texas coast and on the southern tip of the Mississippi delta.

Figure 2. Shoreline change around the United States based on surveys over the past century. All 30 coastal states are experiencing overall erosion due to natural processes (e.g., storms, sea-level rise) and human activity. If the shoreline is uncolored, no data was available. Image credit: USGS, 1985, and taken from Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region).

The Coastal Vulnerability Index (CVI) web page gives detailed maps of each section of the U.S. coast, along with specific reasons why each portion of the coast was assigned the ranking it got. A brief summary:

The Gulf Coast
The Gulf Coast has 55% of its length in the "very high" or "high" vulnerability range. Fully 41% of the coast falls in the "very high" range, far more than the 28% in that category along the Pacific coast and 23% along the Atlantic coast. The region around New Orleans is the most vulnerable region of the entire U.S. coast. The Florida Panhandle, as well as the West Florida coast, are at low to moderate risk because the land is not sinking much, wave heights are lower, and the slope of the land is relatively steep near the coast. The Texas coast is considered to be at a high to very high risk because of the relatively high mean wave height, sinking land, and shallow coastal slope.

The East Coast
The East Coast has 50% of its length in the "very high" or "high" vulnerability range. The highest vulnerability areas are typically high-energy coastlines where the regional coastal slope is low and where the major landform type is a barrier island. A significant exception to this is found in the lower Chesapeake Bay. Here, the low coastal slope, vulnerable landform type (salt marsh) and high rate of relative sea-level rise combine for a high CVI value. The coastline of northern New England, particularly Maine, shows a relatively low vulnerability to future sea-level rise. This is primarily due to the steep coastal slopes and rocky shoreline characteristic of the region, as well as the large tidal range.

The Pacific Coast
The Pacific Coast has 50% of its length in the "very high" or "high" vulnerability range. Areas of very high vulnerability include the San Francisco - Monterey Bay coast and in southern California from San Luis Obispo to San Diego, where the coast is most highly populated. The highest vulnerability areas are typically lower-lying beach areas. The low risk, least vulnerable areas generally occur at rocky headlands along cliffed coasts where the coastal slope is steep, relative sea-level is falling, tide range is large, and wave energy is lower. Examples of these areas are the northern coast of Washington, Monterey, and Cape Mendocino, California.


Figure 3. The Coast Vulnerability Index (CVI) for the U.S.

References
Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region.

National Assessment of Coastal Vulnerability to Sea-Level Rise: Preliminary Results for the U.S. Gulf of Mexico Coast (USGS, 2000).

Jeff Masters

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Wow the blog has slowed to a crawl. Can someone post the shear tendencies for the GOM? I seem to have lost my link.
Member Since: Posts: Comments:
Quoting Gulfsyed:
Wind speeds are really picking up in the GOM, what is the current thought on this storm, just a blob?


Seems like just a blob right now but the water is certainly warm enough for something to try and start. Those storms pushed through the NW FL Panhandle yesterday afternoon, pretty intense storms considering we hadn't seen any rain in over two weeks and have had nothing but Sunny near 100 degree days during that time! I was glad to see the rain and a bit of a cool down.
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Last night we had a severe thunderstorm roll through the island. At one point it was coming down at a rate of over 5.5 inches per hour.

We ended up getting 2.55 inches of rain in a 2 hour span with major lightning.
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lets finish the game
Member Since: July 15, 2006 Posts: 171 Comments: 53808
Wind speeds are really picking up in the GOM, what is the current thought on this storm, just a blob?
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Quoting KEEPEROFTHEGATE:
july 10th is coming


If the train is starting in late June it could be a long train ride July - October!
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Gfs brings strong tropical system close to winward islands in 8days time
Member Since: August 22, 2006 Posts: 0 Comments: 2678
Quoting 69Viking:
A little ealry to be lining up like this isn't it?

july 10th is coming
Member Since: July 15, 2006 Posts: 171 Comments: 53808
A little ealry to be lining up like this isn't it?

Link
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If that wave can survive the shear and stay over water maybe it will turn into something?
Link
Member Since: July 11, 2006 Posts: 14 Comments: 11317

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED JUN 24 2009

TROPICAL WEATHER DISCUSSION...
BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE HAS BEEN ADDED TO THE ANALYSIS ALONG 47W/48W TO THE SOUTH OF 11N. THIS WAVE WAS DETECTED IN VISIBLE IMAGERY FROM 23/1800 UTC...AND CONFIRMED BY STUDYING HOVMOLLER DATA FROM THE LAST 2 TO 3 DAYS. SHOWERS AND THUNDERSTORMS FROM 9N TO 10N BETWEEN 47W AND 50W MAY BE RELATED TO THIS WAVE.

Member Since: July 11, 2006 Posts: 14 Comments: 11317
Hey guys,

I am new to tracking the systems. Could someone give me a rough outline of what the different satellite images are used for? i.e. IR Funktop, Rainbow, Shortwave, AVN, etc...

I would imagine some have to do with cloud density and moisture content, while others have to do with altitude and directional movement.

What do any of you recommend as a good one to take a look at? I notice that many posts have the AVN or RGB views.

BTW - the info you guys (StormW, Levi32, Hur09, wea456 [plus many others]) post is very informative and at the very least entertaining, even if it is just conjecture at times

:-)
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Quoting presslord:
let's go with the yak mini skirt...


Yak, has a different meaning with that image. In particular after lunch (®¿®)
Member Since: June 12, 2005 Posts: 6 Comments: 8186






Member Since: July 15, 2006 Posts: 171 Comments: 53808
Wonder if we'll see something like this in a few days.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
GOES-12 Atlantic Basin WV Loop,WIDE view
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weather 456
what is this area southeast of the southern windwards? QS does not show anything. quite a flare up despite the high shear
Member Since: August 22, 2006 Posts: 0 Comments: 2678
Current Conditions

Uptown, New Orleans, Louisiana (PWS)
Updated: 12 sec ago
Scattered Clouds
98.2 F
Scattered Clouds


Active Advisory: Excessive Heat Warning
Precautionary/preparedness actions...

The excessive heat and humidity will make a dangerous combination
for individuals if proper precautions are not taken. Excessive
heat kills people by taxing the human body beyond its abilities
to cool itself. In a normal year... about 175 americans die from
the heat.

This is a dangerous situation. Children... the elderly... and
people with chronic ailments are usually the first to suffer from
the heat. Heat exhaustion... heat cramps... or in extreme cases...
heat stroke may result from prolonged exposure to these
conditions. Friends... relatives... or neighbors should check on
people at risk.

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Member Since: July 15, 2006 Posts: 171 Comments: 53808
lol
Member Since: July 15, 2006 Posts: 171 Comments: 53808
let's go with the yak mini skirt...
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you pick the type
Member Since: July 15, 2006 Posts: 171 Comments: 53808
Quoting presslord:
KOG...Can I please have the yak coat?!?!?!?!?!

You can keep the seal skin underwear...
the wife says she can cut it down to a full lengh yak evening gown or a short yak mini skirt type dress
Member Since: July 15, 2006 Posts: 171 Comments: 53808
Crawls 11:52 AM CDT on June 24, 2009

Mon and Tues then..the 5 and 6th.
Glad it worked out and they got the ball rolling as well.
Comm was a scarcity till Friday and Sat the 2nd and 3rd.
All those days run into one seems now.


Best of Luck to the Bride and Groom in August.

A Date and Anniversary that will always be Highlighted.
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Quoting Patrap:



When did they get out?
Was a fuzzy time still...in Bucktown.


She was air lifted out, with a critical patient (she had to manually bag the patient since there was on electricity, to keep her alive) on about the 5th or 6th of Sept. The news had been saying for days that Charity had been evacuated BUT they were wrong. I had to call a local state representative and give him my daughters cell phone #, as he was told they were out. Once he verified that no one had been evacuated from Charity, things finally started to happen!!!
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Quoting Levi32:


Too tired to try to dream up something to talk about =P......too quiet to do a video. I'll wait until there's something worth jabbering on about.


lol.....I know that feeling but if your as passionate as me, when there is nothing of interest, try doing a synoptic discussion, talk about the weather in general since TCs are only 10% of tropical weather.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
See this....the Indian Monsoon is dead this year. Precipitation amounts in India are currently below 30% of normal for this time of year.

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with the gfs still latching on to the cv disturbance, and the possibility of a cyclone during the middle of next week. is this the first time that a tropical storm could form in the latter part of june?
Member Since: August 22, 2006 Posts: 0 Comments: 2678
Late June and Early July favors the West Caribbean,BOC and GOM proper.

The First Hurricane Landfall ,Se. La..July 6, 2005

Hurricane Cindy



Hurricane Cindy Wu-archive
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Area of Interest 1:
Member Since: July 8, 2005 Posts: 259 Comments: 24016
Quoting CycloneOz:


The "doom High" ain't never gonna get to the 4 corners area. That would mark the end of our monsoon season and I just don't see that happening.

MODEL ERROR IN PROGRESS! :)

And where's the video with the tidbit today? What's up with that? ;)


Too tired to try to dream up something to talk about =P......too quiet to do a video. I'll wait until there's something worth jabbering on about.

I don't think the high will make it further than New Mexico but never say your monsoon can't be shut down....remember the Indian Monsoon :P
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Quoting Levi32:
ECMWF/GFS comparison 8-10 day 500mb height means continuing to show a retrogressive pattern with the ridge over Texas backing westward to near the 4 corners region during the next 10 days. The mean trough off the eastern seaboard also follows it west. This pattern is still prime for trough-splits and mischief in the NW Caribbean and Gulf of Mexico.



Also notice the very negative NAO(North Atlantic Oscillation) and AO (Arctic Oscillation). This means that the long-wave pattern aloft is very amplified and there is a lot of high-latitude blocking going on, which supports troughs and ridges getting stuck like they are right now over the US, and also supports trough-splits like I mentioned above.



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Quoting Crawls:
Do you believe in omens? My daughter (a nurse), who was stuck in NOLA @ Charity Hospital during Katrina has scheduled her wedding on August 29th.

I hope this month is not the "Calm before the storm" this season.



When did they get out?
Was a fuzzy time still...in Bucktown.
Member Since: Posts: Comments:
Quoting Levi32:
ECMWF/GFS comparison 8-10 day 500mb height means continuing to show a retrogressive pattern with the ridge over Texas backing westward to near the 4 corners region during the next 10 days.


The "doom High" ain't never gonna get to the 4 corners area. That would mark the end of our monsoon season and I just don't see that happening.

MODEL ERROR IN PROGRESS! :)

And where's the video with the tidbit today? What's up with that? ;)
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....furthermore...

if your igloo melts, at least you'll have plenty to drink ...you can't overstate the importance of hydration in the heat...
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Do you believe in omens? My daughter (a nurse), who was stuck in NOLA @ Charity Hospital during Katrina has scheduled her wedding on August 29th.

I hope this month is not the "Calm before the storm" this season.
Member Since: Posts: Comments:
KOG...Can I please have the yak coat?!?!?!?!?!

You can keep the seal skin underwear...
Member Since: Posts: Comments:
ECMWF/GFS comparison 8-10 day 500mb height means continuing to show a retrogressive pattern with the ridge over Texas backing westward to near the 4 corners region during the next 10 days. The mean trough off the eastern seaboard also follows it west. This pattern is still prime for trough-splits and mischief in the NW Caribbean and Gulf of Mexico.

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dam my igoloo will melt away and all my frozen char is going to melt and i guess i should take of my yak coat and walk around in my seal skin underwear its going to be warm
Member Since: July 15, 2006 Posts: 171 Comments: 53808
anything over 90 degrees is hot...I don't care where you are...
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Nangka is following Linfa's footprints:

Member Since: July 31, 2006 Posts: 56 Comments: 8112
Quoting Jedkins01:


if you actually think it gets hot in canada, esspecially eastern canada, you probably should just stop talking all together.


89 degrees in a north lattitude zone with dewpoints in the 60's is cold compared to summer weather on the gulf coast, esspecially with the weaker high lattitude sun
Quoting Jedkins01:


if you actually think it gets hot in canada, esspecially eastern canada, you probably should just stop talking all together.


89 degrees in a north lattitude zone with dewpoints in the 60's is cold compared to summer weather on the gulf coast, esspecially with the weaker high lattitude sun
well 33c/91f air temp with heat index of 39c/102f is pretty warm to me
Member Since: July 15, 2006 Posts: 171 Comments: 53808
What the GFS is predicting is defying most seasonal forecasts including mines. The 12Z run show a weak low level disturbance, remaining open at times, which is much more resonable given the marginal conditions. Wind shear nor dry air seems to its biggest inhibitors but rather SSTs. The wave should probably be watch near 50W and beyond, about mid-next week.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
I really enjoyed R.I.P.ing Andres yesterday just minutes before it was upgraded to a hurricane.

That's a first for me!

Timing is everything! :)

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The SSTs off of Galveston, TX were nearly 94*F yesterday!!! That ridge aloft really has been cooking the waters off Texas lately...

Link

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1980 it were...
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Good Afternoon,

Hurricane Andres Left At Least One Dead; Early Start to Cape Verde Season?
Member Since: July 24, 2005 Posts: 407 Comments: 19076

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.