GEOL 106 Lecture Notes - Lecture 40: Extratropical Cyclone, Coastal Hazards, Tropical Cyclone Warnings And Watches
26 May 2018
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- forecasts of track and intensity of cyclones making landfall on coastlines → help predict height and
extent of storm surge
- can use wind speed, fetch, average water depth to get general idea of elevation of storm surge
o must also predict time of day that surge will arrive → since additional water piled up by storm
is added to level established by astronomical tides
o New England and Atlantic Canada: tidal range is 3m or more → storm surge from tropical or
extratropical cyclone at high tide would be damaging
- predicting geographic extent of storm surge requires detailed info. about land elevation along
coastline
o airbone laser surveying technique LIDAR: used to prepare detailed digital elevation models of
coastlines
o can be entered into computer programs to predict both height and extent of storm surge
o computer programs can take into account forecasts for central atmospheric pressure, size,
forward speed, wind speed, seafloor topography, wind and wave stress, tides, additional
water discharged from rivers (e.g. predicting Hurricane Katrina)
▪ accurate to within 20% values
HURRICANE PREDICTION AND THE FUTURE
- better forecasting, improved evacuation, greater public awareness → drop in hurricane deaths
- coastal populations are going up, coastal development continues in hazard zones → may result in
more hurricane-related deaths
o if increased traffic slows evacuations
o if inexperienced residents are not adequately prepared
o if new residents ignore evacuation procedures
- property damage costs have already increased dramatically
o as more and more people build homes and businesses in coastal zones → except to see costs
continue to rise
10.9 Perception of and Adjustment to Cyclones
PERCEPTION OF CYCLONES
- not all residents of regions of risk perceive the danger
- number of people choose not to evacuate during every hurricane
- people’s pereptio of seere stor risks aries aordig to their experiee
o many people now living in coastal areas are relatively new residents → do not understand the
threat of major hurricane, may underestimate hazard
- incorrect predictions of where or when hurricane will strike can lower risk perception
- accurate risk perception by planners and public alike is key to reducing threats associated with
coastal hazards to those who live there
ADJUSTMENT TO HURRICANES AND EXTRATROPICAL CYCLONES
- warning systems, evacuation plans and shelters, insurance, building design → key adjustments to
hurricanes
o emergency warning systems: gives public max. possible advance notice tha ta potential
hurricane is underway
▪ media broadcasts of watches and warnings
▪ local use of sirens for immediate warnings
o efficient evacuation plans: to ensure most well-organized escape
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