11.3 Tropical cyclone impacts and hazards

Tropical cyclones pack a triple threat: storm surge, heavy rain, and high winds. These primary hazards, along with secondary risks like tornadoes, can devastate coastal and inland areas. The intensity of these dangers depends on storm characteristics and local geography.

Storm surge flooding is a major concern, caused by complex interactions between cyclones and coastal environments. It can penetrate far inland, amplified by waves and tides. Climate change and sea-level rise are making surge impacts worse, highlighting the need for improved coastal defenses and preparedness.

Tropical Cyclone Hazards

Primary Hazards and Their Impacts

Top images from around the web for Primary Hazards and Their Impacts

• 

  NASA Sees Tropical Cyclone Debbie Make Landfall in Queensl… | Flickr View original

  Is this image relevant?

• 

  File:Tacloban Typhoon Haiyan 2013-11-14.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  NASA Sees Tropical Cyclone Debbie Make Landfall in Queensl… | Flickr View original

  Is this image relevant?

• 

  File:Tacloban Typhoon Haiyan 2013-11-14.jpg - Wikimedia Commons View original

  Is this image relevant?

1 of 2

Top images from around the web for Primary Hazards and Their Impacts

• 

  NASA Sees Tropical Cyclone Debbie Make Landfall in Queensl… | Flickr View original

  Is this image relevant?

• 

  File:Tacloban Typhoon Haiyan 2013-11-14.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  NASA Sees Tropical Cyclone Debbie Make Landfall in Queensl… | Flickr View original

  Is this image relevant?

• 

  File:Tacloban Typhoon Haiyan 2013-11-14.jpg - Wikimedia Commons View original

  Is this image relevant?

1 of 2

• Tropical cyclones produce three main hazards with distinct impacts on coastal and inland areas
  • Storm surge causes abnormal sea level rise resulting in severe coastal flooding
  • Heavy rainfall leads to widespread inland flooding, mudslides, and potential dam/levee failures
  • High winds cause structural damage, create flying debris, and pose significant risks
• Secondary hazards extend impact beyond immediate storm path
  • Tornadoes
  • Rip currents
  • Large waves
• Hazard intensity and duration correlate with tropical cyclone strength and size (measured by Saffir-Simpson Hurricane Wind Scale)
• Multiple hazards combine to create compounded risks and challenges for affected populations and emergency responders

Factors Influencing Hazard Severity

• Storm characteristics affect hazard intensity
  • Hurricane intensity
  • Forward speed
  • Size
  • Angle of approach to coast
  • Central pressure
• Local geographic features impact hazard manifestation
  • Coastal shape and characteristics
  • Bathymetry (underwater topography)
• Climate change expected to worsen tropical cyclone impacts
  • Increased frequency of intense storms
  • Sea level rise amplifying storm surge effects

Storm Surge Flooding

Storm Surge Dynamics

• Storm surge results from complex interactions between tropical cyclone and coastal environment
• Maximum potential surge depends on combination of factors
  • Storm intensity
  • Forward speed
  • Direction of approach
  • Local bathymetry
  • Coastline shape
• Surge can penetrate far inland along bays, rivers, and estuaries
  • Flooding possible several miles from coast
• Destructive power amplified by battering waves on top of surge
  • Causes severe erosion
  • Inflicts structural damage to coastal infrastructure
• Surge can overtop and breach coastal defenses (barrier islands, seawalls)
  • Leads to inundation of previously protected areas

Factors Affecting Surge Impact

• Timing relative to astronomical tides significantly influences flooding extent and severity
• Climate change and sea-level rise exacerbate surge impacts
  • Increases frequency and severity of coastal flooding events
• Coastal characteristics affect surge behavior
  • Shallow continental shelves (Gulf Coast) amplify surge
  • Steep shelves (East Coast) produce lower but still dangerous surge
• Surge asymmetry in tropical cyclones
  • Typically higher on right side of storm track in Northern Hemisphere
  • Lower on left side due to offshore winds

Tornado Risks from Hurricanes

Hurricane-Induced Tornado Formation

• Hurricanes create conditions favorable for tornado development
  • Particularly in outer rainbands and right-front quadrant relative to storm motion
• Tornado risk increases as hurricane makes landfall
  • Interaction with land surface friction and wind shear enhances tornadic potential
• Formation often associated with discrete supercells embedded in rainbands
  • Enhanced vertical wind shear promotes rotation
• Hurricane-spawned tornadoes differ from typical supercell tornadoes
  • Generally smaller and shorter-lived
  • Can still cause significant damage

Challenges and Advancements in Tornado Prediction

• Hurricane-induced tornadoes pose unique forecasting challenges
  • Rapid formation with little warning
  • Occur in areas already dealing with other hurricane hazards
• Tornado frequency and distribution vary greatly between storms
  • Influenced by storm structure, environmental conditions, and land interaction
• Advanced Doppler radar technology improves detection capabilities
• Enhanced forecasting techniques aid in tornado warning issuance
• Challenges remain due to tornadoes' rapid formation and movement within hurricane environment

Long-Term Impacts of Hurricanes

Economic and Infrastructure Effects

• Hurricanes cause lasting economic disruption
  • Damage to infrastructure (roads, power grids, communication networks)
  • Business closures and job losses
  • Agricultural devastation (crop destruction, livestock losses)
• Recovery and rebuilding process can span years or decades
  • Strains local and national resources
  • May lead to population displacement and demographic shifts
• Long-term changes in land use patterns and building codes
  • Influences future development in affected areas
  • Shapes coastal management strategies and resilience efforts

Environmental and Ecological Impacts

• Significant changes to impacted ecosystems
  • Altered species composition
  • Habitat destruction (coastal forests, wetlands, coral reefs)
  • Potential introduction of invasive species
• Coastal erosion and barrier island morphology changes
  • Long-term effects on shoreline stability
  • Alters coastal ecosystem dynamics
• Contamination risks persist after storm passage
  • Water source pollution from storm surge and flooding
  • Soil contamination from industrial damage
  • Long-term environmental and public health concerns

Social and Psychological Consequences

• Enduring social and psychological impacts on affected communities
  • Trauma and stress from experience and loss
  • Disruption of community bonds and support systems
• Potential for long-term demographic changes
  • Out-migration from repeatedly impacted areas
  • Shifts in local economy and job markets
• Lasting effects on community resilience and preparedness
  • Changes in risk perception and emergency planning
  • Development of new coping strategies and social support networks