U.S. vulnerability to sea level rise
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
Reader Comments
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Interesting you say that. It gained protection on this date many moons ago.
Antarctic_Treaty
Apparently, you could tune the set to Channel 13, darken the screen to almost black, then turn to Channel 2. Nearby lightning would cause quick lines across the screen and a tornado (supposedly) will produce a white or multi-colored snowy screen, like continuous static.
Its not a good detector and at best is unreliable. There is no way to tell the distance or strength of the lightning strike. I guess tornados spinning generates static electricity that registers on lower UHF frequencies.
Now... with the switch to Digital TV, I will just have to resort to tuning into a local broadcast that provides actual information about approaching storms. The only other option is to look at approaching weather & warnings on-line or (gasp) go outside and observe the conditions manually.
Digital TV is a conspiracy, I tell ya!
AOI #1
AOI #2
You're lucky enough to have both double seabreeze and lots of tropical air.
Nothing stopping anyone from tuning i to that signal. ;)
Believe me, I understand. We have tied record highs here in Mobile for the past few days and I'm more than ready for a drenching downpour.
(1)this blog is dead.
(2)need at Atlantic invest....
As we thought he's trying to revive the CDO. I don't see it lasting very long though. Cold SSTs are just to the west, and outflow to the north is still non-existent.
Are those those bad things Ike, lol ? :)
Good evening Ike
This looks to be a slow starter of a season. Check back around the end of July IMO
I agree that FL gets it share of severe storms but I would not call today a normal day in FL. The storms have been moving from NW to SE all day. This is not the norm. The norm is a SE trade wind bumping up against the West Coast seabreaze. This is what triggers that afternoon storms that at any time can get severe.
HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA
NATIONAL WEATHER SERVICE MIAMI FL
850 PM EDT TUE JUN 23 2009
FLZ063-066>075-168-172>174-240715-GLADES-HENDRY-INLAND PALM BEACH-METRO PALM BEACH-COASTAL COLLIER-INLAND COLLIER-INLAND BROWARD-METRO BROWARD-INLAND MIAMI DADE-METRO MIAMI DADE-MAINLAND MONROE-COASTAL PALM BEACH-COASTAL BROWARD-COASTAL MIAMI DADE-FAR SOUTH MIAMI DADE-
850 PM EDT TUE JUN 23 2009
...SEVERE THUNDERSTORM WATCH FOR PARTS OF SOUTH FLORIDA UNTIL 11 PM EDT...
THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.
.DAY ONE...THIS AFTERNOON AND TONIGHT
THUNDERSTORMS: SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS EVENING AND SOME THUNDERSTORMS MAY POSSIBLY BECOME SEVERE OVER THE WESTERN AND INTERIOR PORTIONS OF SOUTH FLORIDA, INCLUDING INLAND PALM BEACH AND INLAND BROWARD COUNTIES, WITH WIND GUSTS TO NEAR 60 MPH. HAIL TO NICKEL SIZE MAY ALSO BE POSSIBLE ALONG WITH FREQUENT LIGHTNING AND HEAVY RAINFALL.
TORNADOES: THE STRONGEST THUNDERSTORMS WILL ALSO BE CAPABLE OF PRODUCING A BRIEF TORNADO.
WIND: WIND GUSTS TO NEAR 60 MPH MAY BE POSSIBLE TODAY IN THE STRONGEST THUNDERSTORMS.
HAIL: HAIL TO NEAR NICKEL SIZE MAY BE POSSIBLE IN THE STRONGEST THUNDERSTORMS.
FLOODING: THUNDERSTORMS WILL BE CAPABLE OF PRODUCING VERY HEAVY RAINFALL THIS EVENING WHICH MAY PRODUCE PONDING OF WATER ON POORLY DRAINED ROADWAYS.
Goodnight Fellow Wunderbloggers and enjoy the quiet evening (except if you live in South Florida!)
drier air behind the front.
Some say that the 1997 El Nino was stronger than the 1982-1983 event, which unfortunately, I don't have anomalies for.
That being said, the 1982-1983 event was quite strong, evidenced by the fact that the Atlantic was terribly inactive in both years (6 storms the first year, 4 the next). For the 1997 El Nino to surpass that is quite remarkable indeed.
Based on SST anomalies 1997 was clearly stronger and for a longer time.
The only explananation I can think of is that Andres was much stronger yesterday than we ever thought. I'm thinking it could have been as strong as an 80-knot Cat 1, and then when it got stripped of convection it weakened to the intensity that the recon found it at. It was spared from rapid weakening by its impressive low-level structure, and now it's trying to rebuild the CDO.
Which way do you think it entered the tree?
That's impressive in relation to weather and how we put up what we think will help us. That is someones plywood covering on an opening in their house during Andrew. Wow....
Better fastening methods would have prevented this from happeing.
my reason is at least you have a summer here unlike NE sorry NEWXguy SNE was always too cool for me in summer.
Notice how there's kind of a line from SW to NE where the convection rapidly gets cut off. That's pretty much where the dry stable airmass over cold SSTs begins. Andres may be able to rebuild the SE portion of the CDO but I don't expect any significant strengthening phase out of him tonight.
Wilma, Rita, Enrnesto, Katrina, Fay, Charley... how was south florida lucky?
I see this banner on WU and we are all smart enough to know there ain't no way!
http://www.power4home.com/index2.php?hop=ttinc1
Sorry for the rant, but people are getting screwed with this scam and a couple of others that claim the same. If I get banned, so be it.
It is the first post, in months here, talking about cool temps. LOL
3 3 3?
I think he was saying lack of afternoon thunderstorms. He is wrong it has been raining every afternoon here since the dawn of time.
Temperature:11.4°C (52.5°F)
Dew point:9.1°C (48.4°F)
Relative humidity:86%
Feels like:10.7°C (51.3°F)
Wind:W 7km/h (4.3mph)
Wind gusts:13km/h (8mph)
Rainfall since 9am/last hr:0.2mm / 0.0mm
Viewing: 301 - 351
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