Transcript Hurricanes

Hurricanes
Hurricanes help distribute global
energy…
►Move
heat from tropics to higher
latitudes
►Like El Niῆo in Pacific
Where can they form?
►5
to 20 degrees latitude
► Most in North Pacific!
► Hurricanes that affect U.S. begin in Atlantic,
Caribbean, or Gulf
► Move east to west in trade winds
Needed for formation…
►Warm,
deep ocean water
►Converging winds at surface
►Unstable warm air rises
 Low pressure at center
FYI…Lowest pressure systems…
► Wilma
(2005) 882 mbar
► Gilbert (1988) 888 mbar
► Unnamed (1935) 892 mbar
► Rita (2005) 895 mbar
► Allen (1980) 899 mbar
► Katrina (2005) 902 mbar
► “Normal”
sea level
atmospheric pressure is 1000 mbars at
Needed for formation…
►Humid
air at high altitudes
 Vapor condenses releasing energy
►Pre-existing
winds same direction,
altitude, speed
►Upper atmosphere high-pressure
pumps air up and away
Hurricane Circulation
In the northern hemisphere…
►Rising
air moves counterclockwise
surrounding the storm
 Eye wall – greatest wind speed and
heaviest rainfall
►Bermuda
High steers storms
Storm Surge
Video