Hurricane and Typhoon

Hurricane

【DEFINITION】

・The maximum wind speed is a thing of 30 meters/second or more.

・The thing in the Atlantic Ocean, the northeast Pacific Ocean, and a southeast peace on the ocean.

・What occurred in the eastern part Pacific Ocean, the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea.

・It is called a "hurricane season" for six months from June 1 to November 30, and it occurs partly every year. Almost all hurricane will develop in three months late in October from the beginning of August.

 Hurricane is divided into five steps of categories by the strength of the wind. Incidentally, "Katrina" which occurred at the end of August, 2005 recorded the "category 5".

Classification	Wind speed(knot)	Wind speed(mph)	Wind speed(m/s)
Category 1	64-82	74-95	33-42
Category 2	83-95	96-110	43-49
Category 3	96-113	111-130	50-58
Category 4	114-135	131-155	59-69
Category 5	>135	>155	>70

【Record hurricane】

great Hurricane(1780)	Iniki(1992)	Rita(2005)
Galveston 1900(1900)	Mitch(1998)	Wilma(2005)
Camile(1969)	Floyd(1999)	Dean(2007)
Allen(1980)	Isabel(2003)	Felix(2007)
Gilbert(1988)	Ivan(2004)	Gustav(2008)
Hugo(1989)	Jeanne(2004)	Ike(2008)
Andrew(1992)	Katrina(2005)	Sandy(2012)

【Ten strongest hurricane higher ranks in an observation in history】

※The intenseness of hurricane here is based only on the central pressure.

～The minimum central pressure～

Ranking	Hurricane	Year	Pressure (mb/hPa)	Ranking	Hurricane	Year	Pressure (mb/hPa)
1	Wilma	2005	882	6	Katrina	2005	902
2	Gilbert	1988	888	7	Camille	1969	905
3	Labor Day	1935	892	7	Mitch	1998	905
4	Rita	2005	895	9	Dean	2007	906
5	Allen	1980	899	10	Ivan	2004	910

～The central pressure at the time of American landing～

Ranking	Hurricane	Year	Pressure (mb/hPa)	Ranking	Hurricane	Year	Pressure (mb/hPa)
1	Labor Day	1935	892	6	Florida Keys	1919	927
2	Camile	1969	909	7	Okeechobee	1928	929
3	Katrina	2005	920	8	Donna	1960	930
4	Andrew	1992	922	9	Louisiana	1915	931
5	Indianola	1886	925	9	Carla	1961	931

 How much is the size of those damage? Death toll is 1836 and number missing is 705 when Katrina occurred. Moreover, the new damage in which susceptibility gastroenteritis broke out on a massive scale at a refuge place occurred. Otherwise, the jump in an oil price, the influence on a corn market, and the influence on entering school were large.

Typhoon

【DEFINITION】

・The maximum wind speed is a thing of 17 meters/second or more

・The thing on the west North Pacific from 180 degrees east

 So, if hurricane goes into the Japan side from 180 degrees east, it will be called a typhoon.

 The typhoon has the property for a wind high up in the sky to pass, and to move, and to go to north under the influence of rotation of the earth. Therefore, at the low latitude which the east wind is usually blowing, a typhoon goes north gradually, passing to the west. And if it comes to high latitude while the strong west wind (westerlies) is blowing high up in the sky, a typhoon will go to northeast at a quick speed. A typhoon progresses using the energy which the heat emitted when the vapor supplied from the warm sea surface condenses and it becomes a cloud droplet. However, when moving, energy is continuously lost by a sea surface or friction with the ground, and if supply of energy is lost, it will disappear in two or three days. Moreover, if it approaches near Japan, the cold will come to flow in high up in the sky, the original property of a typhoon is lost gradually, and it changes to an "extratropical cyclone." Or supply of thermal energy decreases, and it declines and may change to a "tropical cyclone." The typhoon which landed declines quickly because supply of vapor is severed and also energy is lost by friction of land.