Chapter 11: Hurricanes Tropical weather Tropical weather Anatomy of a hurricane Anatomy of a hurricane Hurricane formation and dissipation Hurricane formation and dissipation Some notable hurricanes Some notable hurricanes Hurricane watches, warnings and forecasts Hurricane watches, warnings and forecasts Modifying hurricanes Modifying hurricanes

Tropical weather

streamlines streamlines tropical wave tropical wave The tropics are close to the equator, where the Coriolis force is too small to balance the pressure gradient force. Thus winds are not geostrophic. The tropics are close to the equator, where the Coriolis force is too small to balance the pressure gradient force. Thus winds are not geostrophic.

Anatomy of a hurricane

tropical cyclone: definition tropical cyclone: definition eye; eyewall eye; eyewall spiral rainband spiral rainband Hurricanes are quite similar to, yet also quite different from mid-latitude storms Hurricanes are quite similar to, yet also quite different from mid-latitude storms

Hurricane formation and dissipation

The right environment convergence convergence trigger trigger trade wind inversion trade wind inversion Convergence of surface winds is often caused by an unorganized cluster of individual thunderstorms Convergence of surface winds is often caused by an unorganized cluster of individual thunderstorms

The developing storm tropical wave tropical wave heat engine heat engine

The storm dies out cutting off the storm’s energy supply cutting off the storm’s energy supply landfall landfall Even though making landfall cuts off a hurricane’s energy supply, the storm is often still quite strong and can even produce tornadoes Even though making landfall cuts off a hurricane’s energy supply, the storm is often still quite strong and can even produce tornadoes

Hurricane stages of development tropical disturbance tropical disturbance tropical depression tropical depression tropical storm tropical storm hurricane hurricane This progression of stages is followed in reverse order as a storm weakens This progression of stages is followed in reverse order as a storm weakens

Hurricane movement role of the ITCZ role of the ITCZ northward movement due to subtropical highs northward movement due to subtropical highs influence of the westerlies influence of the westerlies Because of the Bermuda High, westward-moving North Atlantic hurricanes often take a turn towards the north as they approach North America Because of the Bermuda High, westward-moving North Atlantic hurricanes often take a turn towards the north as they approach North America

Naming hurricanes and tropical storms past practices past practices current protocol current protocol Whenever a hurricane has had a major impact, any country affected by the storm can request that the name of the hurricane be retired by the World Meteorological Organization

Devastating winds and the storm surge location of strongest winds location of strongest winds flooding flooding storm surge storm surge Saffir-Simpson scale Saffir-Simpson scale most hurricane-related deaths are caused by flooding most hurricane-related deaths are caused by flooding

Some notable hurricanes

Camille, 1969 Camille, 1969 Hugo, 1989 Hugo, 1989 Andrew, 1992 Andrew, 1992 Ivan, 2004 Ivan, 2004 Katrina, 2005 Katrina, 2005

Other devastating hurricanes October, 1893 Gulf coast hurricane October, 1893 Gulf coast hurricane August, 1893 Charleston hurricane August, 1893 Charleston hurricane 1970: killer cyclone in Bangladesh 1970: killer cyclone in Bangladesh

Hurricane watches, warnings and forecasts

Hurricane watch Hurricane watch hurricane warning hurricane warning If you live in a hurricane-prone area, it is a good idea to prepare a plan in the event of a hurricane watch or warning If you live in a hurricane-prone area, it is a good idea to prepare a plan in the event of a hurricane watch or warning

Modifying hurricanes

cloud seeding cloud seeding Project STORMFURY Project STORMFURY monomolecular films monomolecular films