Cape Verde-type hurricane

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Hurricane Ivan, a Category 5 Cape Verde-type hurricane

A Cape Verde-type hurricane is an Atlantic hurricane that develops near the Cape Verde islands, off the west coast of Africa. The average hurricane season has about two Cape Verde-type hurricanes, which are usually the largest and most intense storms of the season because they often have plenty of warm open ocean over which to develop before encountering land. The five largest Atlantic tropical cyclones on record have been Cape Verde-type hurricanes. Most of the longest-lived tropical cyclones in the Atlantic basin are Cape Verde hurricanes. While many move harmlessly out to sea, some move across the Caribbean sea and Gulf of Mexico, becoming damaging storms for Caribbean nations, Central America, Mexico, Bermuda, the United States, and occasionally even Canada. Research projects since the 1970s have been launched to understand the formation of these storms.

Origin[edit]

Cape Verde-type hurricanes typically develop from tropical waves which form in the African savanna during the wet season, then move into the African steppes. The disturbances move off the western coast of Africa and become tropical storms or tropical cyclones within 1,000 kilometres (620 mi) of the Cape Verde Islands, usually between July to September. However, Cape Verde hurricanes have formed as early as June or as late as October. An average of two form per hurricane season.[1]

Typical tracks[edit]

Cape Verde-type hurricane tracks

A typical Cape Verde hurricane will form as a tropical depression just south of the Cape Verde islands. It will normally reach hurricane strength in the mid-Atlantic, but sometimes will strengthen closer to Cape Verde or the Caribbean.

The initial track of a Cape Verde storm tends to be generally westward from Cape Verde, with a turn to the north at some stage in the track for most storms lasting more than a few days. Once the cyclone begins approaching South America, a Cape Verde hurricane can take several basic tracks and from there diverge, become extra-tropical, or dissipate.

  1. Allen (1980), on a southern track.
    It can continue to the west, and if it is far enough south, it will cross the Windward Islands into the Caribbean Sea, possibly affecting Venezuela to some degree. From there it will often continue westward into Nicaragua, Honduras, or Belize.[2] For example, Hurricane Joan–Miriam took this southerly route in 1988, causing severe flooding in South America, making landfall in Central America, and continuing into the Pacific Basin, just as Hurricane Irene–Olivia did in 1971. Rarely, a storm will make landfall in South America. Some storms pass unabated into the Gulf of Mexico. Hurricane Ivan of 2004 began with a very southerly route yet it made landfall far to the north in Alabama. Somewhere in the middle of these extremes, storms such as 1980's Hurricane Allen track toward the coast of Mexico, affecting areas from the Yucatán Peninsula to Texas. Many of these southerly hurricanes strike Jamaica, like the Galveston Hurricane of 1915 and Hurricane Gilbert of 1988. Hurricane Janet of 1955 will be remembered as one of the deadliest and strongest storms to strike the Yucatán Peninsula of Mexico.
  2. Georges (1998), on a Caribbean track.
    If the storm is further north, it may travel past the Leeward Islands and into the Greater Antilles. In 1998, Hurricane Georges took a track of this nature as it continued into Mississippi. Slightly further north, and the storm will track through the Bahamas and into Florida in the manner of 1992's Hurricane Andrew.[2] Many of these storms passing through the center of the Caribbean will strike the island of Hispaniola and Cuba, like Hurricane David and Hurricane Frederic did, both in 1979. Some storms on this track will turn to the west once in the Gulf, and thereby make landfall in Texas, as the Galveston Hurricane of 1900 and Hurricane Ike of 2008. Similarly, Hurricane Inez of 1966 followed a Caribbean track that took the storm into the Bahamas where it weakened, only to turn sharply west and make a final landfall in Mexico.
  3. Gloria (1985) struck the East Coast.
    A more northerly storm will often have its track affected by the high pressure that typically occurs over the eastern Atlantic in late summer. As these storms pass north of the Antilles, their tracks begin to curve to the north and to the east of the Florida Peninsula, often sending them away from land. A few storms will track northwest, making landfall in North or South Carolina. Hurricane Hugo of 1989 and Hurricane Fran of 1996 are typical examples. Occasionally storms following this track can accelerate to the north and strike New England. The New England Hurricane of 1938 and Hurricane Gloria in 1985 were two such cases.[2]
  4. Edouard (1996) grazed the East Coast.
    When a storm tracks very far north, its potential for landfall is much less. Some storms do, however, track west-northwest to strike the Atlantic coast of the U.S. and the maritime provinces of Canada, such as 1933 Chesapeake–Potomac hurricane and Hurricane Isabel of 2003, which struck the mid-Atlantic. Both Hurricane Bill (2009) and Hurricane Daisy (1962) were Cape Verde storms that made landfall in Canada, just as Hurricane Luis (1995), Hurricane Earl (2010), and Hurricane Igor (2010) did. If the storm's track is affected significantly, it will often pass near the Eastern U.S., Nova Scotia, and Newfoundland Island and curve back out to sea, where it becomes extratropical over cooler water. An example of such was Hurricane Edouard in 1996. At the extreme, Cape Verde hurricanes can track so far north as to curve all the way to Europe, such as Hurricane Helene of 2006 and Hurricane Isaac of 2000, both of which affected Ireland.
  5. Felix (1989) dissipated in the central Atlantic.
    Sometimes, the subtropical ridge is displaced from its normal position, which allows storms to recurve quickly by being driven around the east side of an upper trough in the central Atlantic, generally missing land completely as they dissipate. Both Hurricane Danielle and Hurricane Karl were affected like this in 2004.[2] In other cases, storms are steered north very early in their development near Cape Verde, such as the 1989 storms Hurricane Erin and Hurricane Felix which both traveled northwest and never threatened land.

Because most Cape Verde-type hurricanes take a near-westward path that starts in the eastern Atlantic, they can avoid the two situations that typically end the life of a tropical cyclone: interaction with land, and movement over cool water. Since storms that far out at sea can go over a week without moving over cooler water or near a landmass, Cape Verde-type hurricanes are some of the longest-lived storms. Hurricane Faith, the third longest lasting Atlantic hurricane on record,[2] was a Cape Verde hurricane. It lasted 16 days total and was a hurricane for 14.[3] Hurricane Joan–Miriam of 1988 and Hurricane Irene–Olivia of 1971 lasted longer, both having crossed narrow parts of Central America and regaining cyclonic motion in the Pacific.

Major Cape Verde-type hurricanes[edit]

The hurricane's peak category is the peak intensity of the hurricane, measured on the Saffir-Simpson Hurricane Scale, or SSHS. Major hurricanes are hurricanes which have reached the third category of the SSHS.

Satellite image of Hurricane Isabel, a Cape Verde-type storm, as it strikes land in 2003 as a massive Category 2. Isabel holds the record for the strongest instantaneous wind speed recorded in an Atlantic hurricane, 233 mph (375 km/h).[4]
Year Name Category
1899 1899 Hurricane San Ciriaco 4
1900 Galveston Hurricane of 1900 4
1926 1926 Miami Hurricane 4
1928 1928 Okeechobee Hurricane 5
1938 New England Hurricane of 1938,
or the Long Island Express
5
1947 1947 Fort Lauderdale Hurricane 5
1957 Hurricane Carrie 4
1958 Hurricane Cleo 5
1960 Hurricane Donna 5
1964 Hurricane Cleo 4
1966 Hurricane Faith 3
1966 Hurricane Inez 4
1979 Hurricane David 5
1979 Hurricane Frederic 4
1980 Hurricane Allen 5
1980 Hurricane Frances 3
1985 Hurricane Gloria 4
1989 Hurricane Hugo 5
1992 Hurricane Andrew 5
1995 Hurricane Felix 4
1995 Hurricane Luis 4
1996 Hurricane Bertha 3
1996 Hurricane Edouard 4
1996 Hurricane Fran 3
1998 Hurricane Bonnie 3
1998 Hurricane Georges 4
1999 Hurricane Floyd 4
1999 Hurricane Gert 4
2000 Hurricane Alberto 3
2000 Hurricane Isaac 4
2001 Hurricane Felix 3
2001 Hurricane Erin 3
2002 Hurricane Lili 4
2003 Hurricane Fabian 4
2003 Hurricane Isabel 5
2004 Hurricane Frances 4
2004 Hurricane Ivan 5
2004 Hurricane Jeanne 3
2004 Hurricane Karl 4
2005 Hurricane Emily 5
2005 Hurricane Dennis 4
2006 Hurricane Gordon 3
2006 Hurricane Helene 3
2007 Hurricane Dean 5
2008 Hurricane Bertha 3
2008 Hurricane Ike 4
2009 Hurricane Bill 4
2009 Hurricane Fred 3
2010 Hurricane Danielle 4
2010 Hurricane Earl 4
2010 Hurricane Igor 4
2010 Hurricane Julia 4
2011 Hurricane Katia 4
2011 Hurricane Ophelia 4
2014 Hurricane Edouard 3

Research[edit]

Twenty nations took part in the GATE research project in 1974, where Douglas DC-6 aircraft examined tropical waves which spawn Cape Verde hurricanes.[5] In 2006, there was a two-month research project known as NAMMA-06 (short for NASA African Monsoon Multidisciplinary Activities)[6] which flew Douglas DC-8's into seedling disturbances in the eastern Atlantic which had the potential to become Cape Verde hurricanes.[7][8]

See also[edit]

References[edit]

  1. ^ Chris Landsea (1997-07-18). "FAQ: HURRICANES, TYPHOONS AND TROPICAL CYCLONES (Part 1 of 2) Subject: A2) What are "Cape Verde"-type hurricanes?". Faqs.org. Retrieved 2009-10-08. 
  2. ^ a b c d e National Hurricane Center; Hurricane Research Division (April 1, 2014). "Atlantic hurricane best track (HURDAT version 2)". United States National Oceanic and Atmospheric Administration. Retrieved October 24, 2014. 
  3. ^ Colin J. McAdie, Christopher W. Landsea, Charles J. Neumann, Joan E. David, Eric S. Blake, and Gregory R. Hammer (2009). Historical Climatology Series 6-2: Tropical Cyclones of the North Atlantic Ocean, 1851–2006 (with 2007 and 2008 track maps included). National Climatic Data Center. p. 161. Retrieved 2009-10-08. 
  4. ^ Richard J. David and Charles H. Paxton (2005). "How the Swells of Hurricane Isabel Impacted Southeast Florida" (PDF). Bulletin of the American Meteorological Society: 1065–1068. doi:10.1175/BAMS-86-8-1065. 
  5. ^ National Oceanic and Atmospheric Administration (2007-02-01). "Feature Stories : Fifty Years of NOAA Hurricane Research". Department of Commerce. Retrieved 2010-01-20. 
  6. ^ R. K. Kakar (Fall 2006). "NASA's Three Pronged Approach to Hurricane Research". National Oceanic and Atmospheric Administration. Retrieved 2010-01-20. 
  7. ^ Jon Hamilton (2006-10-17). "Off Africa's Coast, a Hurricane Nursery". National Public Radio. Retrieved 2010-01-20. 
  8. ^ Marc Kaufman (2006-08-07). "Research Team Seeking Clues to a Hurricane's Birth". Washington Post. Retrieved 2010-01-20. 

External links[edit]