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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2008's Gustav beat out 2007's Humberto in terms of RI.
We'll have to watch the GFS, but it's reminding me more and more of Bertha.
thank you
Tropical Cyclone Outlook (0600z 24JUN)
========================================
The well marked low pressure area (ARB01-2009) over Saurashtra & Kutch and surrounding neighbourhood persists.
Convective clouds are seen over parts of northeast, east central and southeast Arabian Sea, central and southeast Bay of Bengal and Andaman Sea
MONSOON WATCH
===============
The southwest monsoon has further advanced into entire central Arabian sea, some parts of north Arabian sea, south Gujarat state, remaining parts of north Konkan and some more parts of Madhya Maharahtra. The northern limit of monsoon passes through 23.0°N 60.0°E and 23.0°N 65.0°E, Bhuj, Baroda, Nasik, Sholapur, Hyderabad, Kalingapatnam, Paradip, Balasore, Bankura and Gangtok.
Conditions are favourable for further advance of southwest monsoon over remaining parts of Gujarat state during next 48 hours
Not saying im bored and I think its been slow for June (We've already seen our first system lol) But I think this is starting to set up like Bertha. If we see more models jump in later on then I think Bertha part 2 is possible.
What year was Bertha, and where did it hit?
"The 2004 Atlantic hurricane season...was well above average in activity, although a weak El Niño with fifteen named storms and one of the highest Accumulated Cyclone Energy totals ever observed."
The 2004 season started late after a real hot, dry spell too, didn't it?
I think that we will see storms this year, in spite of El Nino conditions...
Hi Chicklit, Good Memory! :)
I will be glad to give you the weather we have been having down here in South Florida the past few days. Gladly.
Don't want no severe storms, just some nice steady all day rain, but I understand where you're coming from.
I know. I have relatives that swore to move because they were so tired of the hurricanes hitting that year!
SFL seems to have had a similar pattern, from conversation here. R u in SFL, or up the coast more?
the same thing i'm talking about we neeeeed it
http://en.wikipedia.org/wiki/Hurricane_Bertha_(2008)
Hi Wxhatt,
2004 was a hurricane year to remember if you lived in Central Florida...we were still recovering when 2005 and Katrina occurred.
Link
Ya 2004 is a year I'll never forget.
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUN 24 2009
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.
BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.
...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 53W/54W S OF 12N MOVING W NEAR 15 KT.
THIS WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS.
SATELLITE IMAGERY INDICATES THE WAVE COINCIDES WITH AN INVERTED-V CLOUD PATTERN IN THE LOW-LEVEL CLOUDS. SCATTERED MODERATE CONVECTION IS FROM 7N-12N BETWEEN 48W-57W.
It looks weak and torn apart by shear but ain't dead yet...
Hurricane Heat Potential
It's a shame, as we were looking forward to some more rain.
Yep, I took a drive East End on Monday and it was a good rain from Bodden Town all the way to East End, right now we're having a fairly decent rain In South Sound where I live, but as you know it can being raining at your place and 300 feet away not a drop is falling.
Not heating up much N of 20N so far.
Glad u are getting some rain.
TAMPA - The 2004 hurricane season was quiet the first two months, until Bonnie, a tropical storm, brushed through the Panhandle. Then the four-hurricane procession started. The drumbeat of hurricanes - impatient Charley, plodding Frances, savage Ivan and copycat Jeanne - spun out of the Atlantic Ocean storm factory and shot toward Florida during a rare run of atmospheric ill fortune.
Oh please, do not be a repeat.
I think we'll see something sooner than two months into hurricane season.
Best I could find:
Most prominent differences are that it's warmer off of New England and in the east Pacific this year than 2004, but 2004 was warmer in the eastern Atlantic, and very slightly warmer in the Gulf of Mexico than this year, but this is only one analysis. The Caribbean was about the same temperature.
June 13, 2004:
June 13, 2009:
Honestly, as much wind damage as Gustav.
On the spot, I would estimate a single 65 mph gust.
Its warming up, but more slowly than the gulf or Caribbean.
SSTs:
26C Isotherm (depth of the 26C layer):
TCHP for the Atlantic Basin:
Most years do....even 2005 looks pretty close on that map....it's global and not very detailed. I'd need a better graphic to demonstrate the differences effectively. That's why I pointed out the differences.
Just kidding, futuremet.
And others: do NOT place a magnet near your harddrive unless you do no like your software or data.
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