"U.S. Flood Modeling" - Presented at the RAA's Cat Modeling Conference 2014

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RMS recently spoke at the RAA's Catastrophe Modeling conference in Orlando, discussing U.S. flood risk, specifically about flood modeling, recent successes and future progress to improving the state of flood modeling.

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"U.S. Flood Modeling" - Presented at the RAA's Cat Modeling Conference 2014

  1. 1. U.S. FLOOD MODELING Clare Salustro Manager, Model Product Management, Americas Climate ©2014 Risk Management Solutions, Inc. Confidential
  2. 2. Where have we been? Where are we now? What’s changed? What’s coming?
  3. 3. JULY 2013 US FLOOD TIMELINE MTA Cat Bond is first ever Cat Bond for storm surge JANUARY 2014 JUNE 2012 Partial delay of Biggert-Waters Biggert-Waters NFIP Reform Act signed into law ? SEPTEMBER 2008 AUGUST 2005 Hurricane Katrina Hurricane Ike $2.7 Bn NFIP loss $16.3 Bn NFIP loss ©2014 Risk Management Solutions, Inc. Confidential OCTOBER 2012 Hurricane Sandy $7.8 Bn NFIP loss
  4. 4. Event ©2014 Risk Management Solutions, Inc. $16.3B Hurricane Sandy 2012 $7.8B Hurricane Ike 2008 $2.7B Hurricane Ivan 2004 $1.6B 2011 $1.3B 2001 $1.1B Louisiana Flood 1995 $585M Tropical Storm Isaac Over half of total NFIP payout (since program began in 1978) from just two years – 2005 and 2012 – driven by coastal flood loss 2005 2012 $531M Hurricane Isabel 2003 $493M Hurricane Rita 2005 $472M Hurricane Floyd 1999 $462M Tropical Storm Lee 2011 $445M Hurricane Opal 1995 $406M Hurricane Hugo 1989 $376M Hurricane Wilma 14 of top 15 NFIP claims related to Tropical Storms and Hurricanes Hurricane Katrina Tropical Storm Alison Flood risk in U.S. is dominated by coastal flood Claims Hurricane Irene NFIP: TOP 15 LOSSES Year 2005 $365M Confidential
  5. 5. NFIP: LOSS HISTORY Flood risk in U.S. is dominated by coastal flood Total NFIP Claims in $Bn (1978-present) Contribution to total (%) Flooding from hurricanes and tropical storms 36.5 87% Non-tropical cyclone-related flooding 5.7 13% TOTAL 42.2 100% Source ©2014 Risk Management Solutions, Inc. Confidential
  6. 6. COASTAL FLOOD MODELING ISN’T EASY Storm surge processes are complex •  •  Must account for hurricane characteristics over lifetime of storm Must model at very high resolution RMS approach has evolved over time and was well validated by recent events such as Sandy ©2014 Risk Management Solutions, Inc. Confidential
  7. 7. IT’S NOT JUST LANDFALL CHARACTERISTICS THAT MATTER Windspeed Cannot assume 1:1 relationship between wind and surge severity at landfall Storm surge impacts can be more severe than indicated by landfall characteristics –  Sandy (2012) –  Ike (2008) –  Katrina (2005) 170 160 150 140 Cat 5 Cat 4 130 120 110 100 90 80 ©2014 Risk Management Solutions, Inc. (mph) at landfall Cat 3 Cat 2 Cat 1 Confidential 22 20 18 16 14 12 10 8 6 4 2 Surge height (feet) Katrina Cat 5 Ike Cat 4 Sandy Cat 3 Cat 2 Cat 1
  8. 8. DIFFERENT APPROACHES TO STORM SURGE MODELING Empirical Models SLOSH Hydrodynamic Models •  Lack of observations to train on across all regions •  Doesn’t account for surge development over life of storm •  Difficult to deal with complex coast-lines, bays, and barrier islands •  (Sea, Lake, and Overland Surge from Hurricane) •  Operational focus, widely used for disaster planning •  Not certified for FEMA flood modeling studies •  Grid resolution decreases away from central point •  Physics-based calculation of time-stepping storm surge •  Considered best practice for FEMA flood modeling studies •  Can control grid resolution – put fine resolution grid cells where they’re needed most ©2014 Risk Management Solutions, Inc. Confidential
  9. 9. DIFFERENT APPROACHES TO STORM SURGE MODELING Empirical Models SLOSH Hydrodynamic Models •  Lack of observations to train on across all regions •  Doesn’t account for surge development over life of storm •  Difficult to deal with complex coast-lines, bays, and barrier islands •  (Sea, Lake, and Overland Surge from Hurricane) •  Operational focus, widely used for disaster planning •  Not certified for FEMA flood modeling studies •  Grid resolution decreases away from central point •  Physics-based calculation of time-stepping storm surge •  Considered best practice for FEMA flood modeling studies •  Can control grid resolution – put fine resolution grid cells where they’re needed most ©2014 Risk Management Solutions, Inc. Confidential
  10. 10. NUMERICAL APPROACH: SUPERCOMPUTING RESOURCES REQUIRED… ©2014 Risk Management Solutions, Inc. Required 500 CPUs and 60 terabytes of disk-space to generate RMS North Atlantic Hurricane Model storm surge stochastic set Confidential
  11. 11. RMS SURGE MODELING: NESTED MESH FRAMEWORK REGIONAL MESH ©2014 Risk Management Solutions, Inc. TRACK SET WIND FIELD LOCAL MESH FLOOD DEPTHS Confidential
  12. 12. HIGH RESOLUTION COASTAL FLOOD MODELING Detailed bathymetry and coastal topography: Southern Louisiana •  Resolutions as fine as 100m •  Ability to model complex flows of water in and out of bays and harbors •  Manage and underwrite coastal flood risk with confidence, down to the local level ©2014 Risk Management Solutions, Inc. Confidential
  13. 13. ABLE TO MODEL REALISTIC COASTAL FLOODING Previous model extent (parametric model) ©2014 Risk Management Solutions, Inc. Current model extent (full hydrodynamic model) Confidential
  14. 14. ABLE TO MODEL REALISTIC COASTAL FLOODING Previous model extent (parametric model) ©2014 Risk Management Solutions, Inc. Current model extent (full hydrodynamic model) Confidential
  15. 15. RMS Storm Surge Model WELL VALIDATED DURING SANDY •  RMS model as good as best data developed by FEMA •  Verified against over 200 independent flood observations ©2014 Risk Management Solutions, Inc. Confidential FEMA Flood Extent
  16. 16. LESSONS LEARNED FROM SANDY •  •  •  High-value contents in basements within central business district took many by surprise Highlighted gaps in data capture, limited exposure information Sandy Data Call currently underway ©2014 Risk Management Solutions, Inc. Confidential
  17. 17. WHERE DOES THIS LEAVE US NOW? Only%modeling% company%that% integrates%a%full% dynamic%storm%surge% model%into%its% hurricane%model%suite%% ©2014 Risk Management Solutions, Inc. High%quality,%well9 verified%model%for% driver%of%U.S.%flood%loss% Confidential Viable%alternate%view% of%risk%from%FEMA%for% coastal%flood,%available% now%
  18. 18. COASTAL FLOOD VIEW ALREADY AVAILABLE 100-YEAR FLOOD ELEVATION: FEMA VERSUS RMS FEMA ©2014 Risk Management Solutions, Inc. Confidential RMS
  19. 19. Completing the U.S. Flood Solution
  20. 20. GOAL: Develop modeling solution covering all sources of flooding in US !  Tropical Cyclone Surge !  Tropical Cyclone Precipitation !  Non-Tropical Cyclone Precipitation ©2014 Risk Management Solutions, Inc. Confidential
  21. 21. GOAL: Develop modeling solution covering all sources of flooding in US "  Storm Surge within Hurricane Model "  Tropical Cyclone Surge !  Tropical Cyclone Precipitation !  Non-Tropical Cyclone Precipitation ©2014 Risk Management Solutions, Inc. Suite of US Flood products: Confidential
  22. 22. GOAL: Develop modeling solution covering all sources of flooding in US "  Storm Surge within Hurricane Model "  Tropical Cyclone Surge !  Tropical Cyclone Precipitation !  Non-Tropical Cyclone Precipitation ©2014 Risk Management Solutions, Inc. Suite of US Flood products: !  US Flood HD Model Confidential coming'soon!!
  23. 23. GOAL: Develop modeling solution covering all sources of flooding in US "  Storm Surge within Hurricane Model "  Tropical Cyclone Surge !  Tropical Cyclone Precipitation !  Non-Tropical Cyclone Precipitation ©2014 Risk Management Solutions, Inc. Suite of US Flood products: !  US Flood Hazard Data Product !  US Flood HD Model Confidential coming' soon!!
  24. 24. New US Inland Flood model (lower 48 states) set to be released on RMS(one) U.S. Major River Basins Probabilistic model is precipitationdriven Includes tropical cyclone and non-tropical cyclone precipitation Covers both floodplain (major and minor) and off-floodplain (i.e. flash flooding) events Continuous simulation accounts for antecedent conditions
  25. 25. LARGEST MODEL EVER BUILT Number of grid cells in US Inland Flood Model Number of grid cells in US Storm Surge Model 32 Mn! ©2014 Risk Management Solutions, Inc. 5.7 Bn! Confidential
  26. 26. WHY NOW? Not computationally possible previously We’re able to do it now because: •  Migrated heavy processing from conventional CPUs to GPUs – gain of over 200x •  RMS(one) reduces storage need for client ©2014 Risk Management Solutions, Inc. Confidential
  27. 27. BUILDING MODELS IN RMS(ONE) HD Simulation: Allows for continuous simulation of events –  Similar meteorological events can lead to very different hazard & loss events o  Antecedent conditions strongly influence the severity of a flood –  Able to capture clustering and correlation •  New financial model enabled by Contract Definition Language (CDL) –  Properly model hours clause and complex flood policy terms •  ©2014 Risk Management Solutions, Inc. •  Performance offered by the Cloud Confidential
  28. 28. US FLOOD MODEL COMPONENTS Geospatial Data Underlying elevation dataset and derivative elements ©2014 Risk Management Solutions, Inc. Stochastic Event Module Hazard Module Vulnerability Module Define precipitation years Compute resulting flood hazard footprints Calculate damage based on risk item characteristics Confidential Financial Module Quantify financial loss
  29. 29. HIGH QUALITY INPUT DATA High-Quality, High-Resolution Geospatial Data is critical to flood modeling •  •  •  ©2014 Risk Management Solutions, Inc. Confidential Source resolution for elevation data improves quickly Using latest enhanced version of National Hydrography Dataset (NHD): NHDPlusV2 RMS spent several person-years on QA of data layers –  Fed findings back to NHDPlus data providers to help improve their product
  30. 30. EXAMPLE QA TASK By comparing with Google Earth, corrected misplaced river segment in elevation dataset Actual path ©2014 Risk Management Solutions, Inc. Actual path Confidential
  31. 31. HAZARD SIMULATION APPROACH Tropical Cyclone Precipitation Precipitation Simulate the source of the flooding: tropical cyclone and non-tropical cyclone Non-Tropical Cyclone Precipitation Rainfall Runoff Routing Defense Inundation Understand how rainfall enters the water systems Propagate the water through major and minor river systems Account for mitigation measures and possibility of flood defense failures Form a footprint of saturation and flooding Source: cpc.ncep.noaa.gov ©2014 Risk Management Solutions, Inc. Confidential
  32. 32. HAZARD SIMULATION APPROACH Precipitation Simulate the source of the flooding: tropical cyclone and non-tropical cyclone ©2014 Risk Management Solutions, Inc. Rainfall Runoff Routing Defense Inundation Understand how rainfall enters the water systems Propagate the water through major and minor river systems Account for mitigation measures and possibility of flood defense failures Form a footprint of saturation and flooding Confidential
  33. 33. Comparison of 100 year model hazard with FEMA maps - Memphis, TN RMS FEMA ©2014 Risk Management Solutions, Inc. Confidential
  34. 34. RMS FLOOD HAZARD DATA PRODUCT Coming soon! –  Coverage: 48 states & District of Columbia –  All sources of flooding: o  Coastal flooding from storm surge o  Tropical cyclone precipitation o  Non-tropical cyclone precipitation –  Return periods: o  Multiple return periods, 20 years to 1000 years o  Catchments by hydrological regions –  RMS(one) functionality: o  Location-level underwriting, flood zone lookup frequency and severity with return period and flood depth o  Accumulation management o  Flood hazard visualization ©2014 Risk Management Solutions, Inc. Confidential
  35. 35. Example 200-year return period hazard map RMS FLOOD HAZARD DATA PRODUCT Fully integrated into RMS(one) ©2014 Risk Management Solutions, Inc.
  36. 36. RMS VS. FEMA: COMPARABLE BUT DIFFERENT ©2014 Risk Management Solutions, Inc. Confidential
  37. 37. RMS VS. FEMA: COMPARABLE BUT DIFFERENT Return Period (years) FEMA FIRMs Flood Extent Flood Elevation 20 ✓ ✓ 50 ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ 100 Flood Extent ✓ Flood Elevation RMS Hazard Data Product ✓ (BFEs) 250 500 ✓ 1000 ©2014 Risk Management Solutions, Inc. Confidential
  38. 38. RMS VS. FEMA: COMPARABLE BUT DIFFERENT Component FEMA FIRMs RMS Hazard Data Product Mapping methodology Varies by region Consistent for entire lower 48 states Geospatial data vintage (e.g., elevation) Varies by region Current Update frequency Varies by region, sometimes > 20 years Can incorporate changes quickly n/a Uses same event set as RMS North Atlantic Hurricane model Correlation with other perils ©2014 Risk Management Solutions, Inc. Confidential
  39. 39. Where have we been? NFIP reform will happen, eventually Can the private market take on more of the US flood risk? Where are we now? What’s changed? RMS tools already exist… What’s coming? ©2014 Risk Management Solutions, Inc. Confidential …and more are coming

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