Hurricane Hazards In Depth

Strong Winds

• 157 mph in Category 5 storms
• not as fast as tornadoes, but much more widespread
• wind velocities are higher on the “right side” of the cyclone
  • speed of storm and wind speed
  • highest storms surges also occur along the right side

Storm Surge/Flood/High Waves

• ocean water pushed towards the shore by strong winds (95% of surge)
  • rough, turbulent waves
  • especially close to and on the right side of the eyewall
• eye is a low-pressure zone; seawater builds up (5% of surge)
• especially bad if it coincides with the high tide
  • water level increased by up to 30 feet
• water moves inland which leads to flooding
• Hurricane Katrina (category 5) in Gulfport, MS (August, 29, 2005)
  • peak surge estimated at 28 feet in this location
• 59% of deaths in the US related to hurricanes from 1970-1999 were due to inland flooding
  • related to storm surge and heavy rainfall

Heavy Rainfall

• often after passage of the hurricane
• dying hurricane holds massive volumes of water
• causes inland flooding
• can be caused by low-intensity hurricanes (like a Category 1) or tropical storms