Hurricanes Impacting Hawaii. Hawaii Hurricane Impacts. Some Common Comments. MFE 658 Lecture 3b Hurricane Impact. Hurricane Iniki

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1 Hurricanes Impacting Hawaii MFE 658 Lecture 3b Hurricane Impact Hurricane Iniki Hurricane s in Hawaii Hurricane hazards Hurricane forecasting Hurricane risk assessment Hurricane Neki 1 2 Some Common Comments No hurricane has made landfall on Oahu. Only Kauai gets hit The Big Island and Maui were struck by a hurricane in 1872 Dot 1959, Iwa 1982, and Iniki 1992 all impacted Kauai Mountains protect us If so, why don t the mountains of Puerto Rico or Taiwan protect them? There is no Hawaiian word for hurricane No Hawaiian Term actually is not a surprise, since words such as Hurricane and Typhoon arise from local words for the winds observed. David Malo (1843) defined five different Kona Winds. Tropical Cyclone tracks within 200 miles of the Hawaiian Islands since Hawaii Hurricane Impacts 3 4

2 Hawaii Hurricane Climatology Central Pacific Hurricane Climatology Note: more hurricanes occur in the central Pacific during strong el niño years. Why? Hurricane tracks in the central Pacific from Number of hurricanes per month in the central Pacific. 5 6 Human Impacts Economy - To-date cost of Iniki $2.8 Billion FY2005 Estimated Impact on General Fund Tax Revenues $3.6 Billion More Iniki Impacts 90% of structures on Kauai affected 14,118 damaged or destroyed 30% telephone poles down 3 years later unemployment 12% Social fabric altered-10% move away REMEMBER: This coincided with the bursting of the Japan Bubble Economy of the late 1980 s. 7 8

3 Hurricane Impact Saffir/Simpson Hurricane Scale Category mph Storm surge 4-5 ft Category mph Storm surge 6-8 ft Category mph Storm surge 9-12 ft Category mph Storm surge ft Category 5 > 155 mph Storm surge > 18 ft Energy of winds = wind velocity squared: E = V 2 A doubling of the wind speed (e.g., from 70 to 140 mph) results in four times the destructive energy. Energy of winds = wind velocity squared: E = V 2 A doubling of the wind speed (e.g., from 70 to 140 mph) results in four times the destructive energy High winds flying debris Triple Threat Flash Floods Large Surf TRIPLE THREAT TRIPLE THREAT FROM TROPICAL CYCLONES (winds & low pressure) High Winds Heavy Rains Injuries and Loss of Life Structural Damage Destruction of vegetation/crops Flooding of coastal areas Erosion of Beaches Saline Intrusion loss of fertility Loss of Power/Communications Fires - Urban and Brush Contamination of Water Supply Land Subsidence Flooding of Inland Areas Mud and Landslides 11 12

4 Hurricane Iniki Hurricane Hazards in Hawaii The storm surge and storm waves are greatest just to the right of the storm track. Why? The storm surge and storm waves are greatest just to the right of the storm track. Wind hazard is greatest on exposed ridges and mountain slopes. Flash flood hazard is greatest near steam beds Past Hurricane Impact: Death vs Damage Hurricane Impact Deaths Damage Population change and hurricane strikes for Miami Dade County The record is dominated by a few extreme events: Galveston hurricane of 1900 and Katrina in 2005 (2005 Dollars) 15 16

5 The strength of a storm surge depends on: Wind strength Length and duration of the fetch Angle between storm path and coastline (90 optimal) Shapes of coastline and continental shelf. Convergence of wind-driven currents, bays and estuaries tend to amplify the surge. Gently sloping continental shelf enhances surge. The stage of the astronomical tide is important. Current (N.H.) wind Coriolis force deflects ocean currents to the right of the wind in the Northern Hemisphere Cyclonic surface wind stress causes cyclonic gyre in ocean with a dome of water, upwelling, and surface water divergence. Low surface air pressure also contributes Elevated Sea-Level - Elevated Sea-Level Flooding of coastal areas Erosion of Beaches Saline Intrusion loss of fertility Storm surges are historically responsible for the greatest numbers of deaths and they cause some of the worst damage

6 Debris line from Iniki storm surge ±8000 people died in the storm surge Ivan Aftermath 52 deaths in US 70 deaths in Caribbean Storm surge, before and after hurricane Camille

7 Katrina ±1800 deaths in US Katrina Aftermath Katrina Aftermath Hurricane Wind Damage Oil production takes a hit from Rita and Katrina. Wind Speed in hurricane Celia as it passed Gregory, TX

8 Hurricane Wind Damage Iniki Wind Damage Hurricane Wind Damage Tangential Wind Profile Wind damage to Darwin, Australia from cyclone Tracy. Similar wind damage occurred in Andrew

9 Port Allen Pressure Trace Wind Distribution 140 Assuming cyclostrophic balance, dp/dt ~ dv/dy miles Cyclostrophic tangential wind distribution calculated for Port Allen Wind Distribution Tornados in Hurricanes Observed wind gusts distribution at Lihue during Iniki. It is the wind gusts that do the damage. Strongest tornadoes are found in right front quadrant. Hurricane moving toward 360, range rings at 100 km

10 Hurricane Rains and River Flooding FLOODING Precipitation Precipitation Hydrologic Duration Intensity Aspects Precipitation Duration Evolution of Tropical-Storm Scale Circulations! Evolution of Mesoscale Features convective bands and elements Moisture availability in surroundings Orographic Anchoring and Enhancement Instability Replenishment for New Storms Non-Interfering Up and Down Drafts TC Stagnation TC in streamline col region. No steering current.! TC surrounded by highs. Good environment for TC. TC approaching another low, may cause TC to stagnate or loop. High to NE may block progress of northeastward moving storm. Steering currents from opposite directions

11 Ivan Aftermath North Carolina Flooding Heavy rains & Flooding in NC Slow moving tropical cyclones result in very large rainfalls Hurricane Mobile Homes Hurricane Forecasting NWS Hurricane Advisories Hurricane Watch - Hurricane may threaten the coast. Issued ~ 36 hours in advance Hurricane Gridlock Hurricane Warning - Hurricane conditions are expected within 24 hours. Issued ~12-24 hours in advance. Hurricane forecasting involves predicting the future track and intensity of a hurricane

12 Hurricane Forecasting Hurricane forecasting involves predicting the track and intensity of a hurricane. Hurricane tracks are erratic and difficult to predict. A combination of observations, numerical model output, and climate data are used to forecast hurricane tracks. More progress has been made in hurricane track forecasting than in forecasting hurricane intensity change. Hurricane Forecasting Cloud Drift Winds Satellite Rainfall Measurement IR Imagery from Bonnie 8/25/ UTC (Blue Rings at 100 and 350 km Radius) Hurricane Katrina 47 48

13 Hurricane Forecasting Hurricane Risk Analysis Hurricane Rita Simulation using a high resolution model with data assimilation The Insurance Crisis of 1993 Pre-Iniki Hurricane wind peril coverage was an addon to fire and theft. Iniki wiped out all profits of the homeowners insurance industry in Hawaii since its founding. Hawaii is a small revenue source for big firms and provided a disproportionately large loss. Iniki occurred within 18 days of Andrew (Miami) and Omar (Guam). The global re-insurance industry was reeling. In both Florida and Hawaii companies went bankrupt or attempted to withdraw. Serious problems for the real estate markets. Band Aid Solutions Florida created a catastrophe fund which is a reinsurer. Florida also created a wind pool (insurer of last resort) for high-risk properties (think east of I-95 in Miami). Hawaii created the Hawaii Hurricane Relief Fund (sounds like a Red Cross operation), a primary insurer. The HHRF filled in until the industry recovered. Now in repose, still on the books 51 52

14 Risk Modeling Issue : events like Hurricanes are very rare, Iniki is at least a centennial time scale event Normal actuarial techniques are not applicable In 1985 Karen Clark founded Applied Insurance Research and presented the first Hurricane risk model A model consists of Risk Modeling (cont) 1.A peril. Here a hurricane 2.The model simulates a massive number of hurricanes by projecting forward perhaps 100,000 years using statistical approaches. 3.The model then assesses impacts upon a portfolio of properties (vulnerability). 4.The model then applies actuarial functions to produce insured losses. 5.Based upon these projected losses, rates are determined Risk Modeling (cont) Risk Modeling (cont) These went over like the proverbial lead balloon. 1. The methodology is strange to those familiar with traditional insurance practice (think life insurance). 2. Everybody s rates were going up. 3. Insurance companies are evil anyway. Florida created a Commission on Hurricane Loss Projection Methodology Commission reviews models for use in the State of Florida Due to Sunshine Laws, modeling companies resist public presentation of trade secrets. Florida Commission created a professional team to conduct on site audits

15 Risk Modeling (cont) Risk Modeling (cont) The Florida Professional Team consists of a lead and back-up in the areas of : 1. statistics 2. meteorology (I have acted as reviewer for this section) 3. structural engineering 4. actuarial science 5. computer science The Pro Team signs non-disclosure forms We audit against standards developed by the Florida Commission via a public process We file reports on our findings We attest to our findings in public hearings We work with the Commission to develop new, improved standards (raising the bar) Risk Modeling - Hawaii Hurricane Risk Analysis Hawaii uses a simpler process Three consultants are retained 1. A meteorologist 2. A structural engineer 3. An actuary 1 and 3 are both members of the Florida Pro Team The consultants review applications of the models to the Hawaii situation The first question asked is whether or not the model has been accepted in Florida 59 60

16 Hurricane Risk Analysis Wind Model Validation The characteristics of the hurricane that are needed to produce an estimate of wind speed at a site are as follows: (i) Central Pressure Difference (ii) Radial Pressure Profile Parameter (iii) Radius to Maximum Winds (iv) Storm Translation Speed (v) Storm Track (vi) Latitude and Longitude of Site (vii) Surface Roughness at the Site (viii) Distance of the Site from the Coast Vulnerability Functions Questions? Damage is characterized by four parameters: occupancy, number of stories, structural system, and exterior cladding strength. For residential structures, the 21 structure types (e.g., frame, Heavy Timber Joisted Masonry, Timber, Weak- Cladding, etc.) The vulnerability functions in the model were developed largely on the basis of claims data from Hurricane Luis 63 64