Commonwealth of Massachusetts 2013 State Hazard Mitigation Plan Section 11. Hurricanes and Tropical Storms ....................................................................................... 11-1 11.1 General Background .................................................................................................................. 11-1 11.1.1 Tropical Storms ............................................................................................................ 11-1 11.1.2 Hurricanes .................................................................................................................... 11-1 11.1.3 Saffir/Simpson Hurricane Scale ................................................................................... 11-3 11.1.4 SLOSH Mapping .......................................................................................................... 11-4 11.2 Hazard Profile ......................................................................................................................... 11-10 11.2.1 Location...................................................................................................................... 11-10 11.2.2 Previous Occurrences ................................................................................................. 11-12 11.2.3 Frequency ................................................................................................................... 11-18 11.2.4 Probability of Future Occurrences ............................................................................. 11-19 11.2.5 Severity ...................................................................................................................... 11-22 11.2.6 Warning Time ............................................................................................................ 11-23 11.3 Secondary Hazards .................................................................................................................. 11-23 11.4 Climate Change Impacts ......................................................................................................... 11-23 11.5 Exposure .................................................................................................................................. 11-24 11.5.1 Population .................................................................................................................. 11-24 11.5.2 State Facilities ............................................................................................................ 11-25 11.5.3 Critical Facilities ........................................................................................................ 11-31 11.5.4 Economy .................................................................................................................... 11-32 11.6 Vulnerability ........................................................................................................................... 11-33 11.6.1 Population .................................................................................................................. 11-33 11.6.2 State Facilities ............................................................................................................ 11-34 11.6.3 Critical Facilities ........................................................................................................ 11-47 11.6.4 Economy .................................................................................................................... 11-47 TABLES Table 11-1. Saffir/Simpson Scale (NOAA) ............................................................................................. 11-4 Table 11-2. History of Hurricanes and Tropical Storms ........................................................................ 11-12 Table 11-3. FEMA HURRICANE-RELATED DISASTER DECLARATIONS (1954 to 2012) ......... 11-13 Table 11-4. Estimated Population Exposure to the Hurricane Hazard .................................................. 11-24 Table 11-5. Total State Building Replacement Cost Value Exposed to the Hurricane/Tropical Storm Hazard .................................................................................................................................................... 11-25 Table 11-6. State Building Exposure in the SLOSH Zones (Cumulative), by County .......................... 11-26 Table 11-7. State Facilities in the SLOSH Zones (Cumulative), By State Agency ............................... 11-27 Table 11-8. Change in Number of State Buildings in SLOSH Zones by County, 2009 to 2012 ........... 11-29 Table 11-9. Change in Value of State Buildings in All SLOSH Zones by County, 2009 to 2012 ........ 11-30 Table 11-10. Critical Facility Exposure to Surge Inundation SLOSH Zones ........................................ 11-31 Table 11-11. Critical Facility Exposure to Surge Inundation SLOSH Zones, by County ..................... 11-31 Table 11-12. Number of Bridges in the SLOSH Hazard Zones by County ........................................... 11-32 Table 11-13. Area Located In The Slosh Zones (Square Miles) ............................................................ 11-33 Commonwealth of Massachusetts 2013 State Hazard Mitigation Plan Table 11-14. Estimated Shelter Needs - Wind Only Analysis ............................................................... 11-34 Table 11-15. Estimated Potential State-Owned and Leased Building Loss from Hurricane Category 4 Storm Surge by County .......................................................................................................................... 11-40 Table 11-16. Estimated Potential State-Owned and Leased Building Loss from Hurricane Category 4 Storm Surge by State Agency ................................................................................................................ 11-41 Table 11-17. Estimated Building Loss—Wind Only ............................................................................. 11-43 Table 11-18. Estimated Economic Loss - Wind Only Analysis—Tropical Storm ................................ 11-48 Table 11-19. Estimated Economic Loss - Wind Only Analysis— Category 1 Hurricane ..................... 11-48 Table 11-20. Estimated Economic Loss - Wind Only Analysis—Category 2 Hurricane ...................... 11-49 Table 11-21. Estimated Economic Loss - Wind Only Analysis— Category 3 Hurricane ..................... 11-49 Table 11-22. Estimated Debris - Wind Only Analysis— Tropical Storm ............................................. 11-50 Table 11-23. Estimated Debris - Wind Only Analysis— Category 1 Hurricane ................................... 11-50 Table 11-24. Estimated Debris - Wind Only Analysis— Category 2 Hurricane ................................... 11-51 Table 11-25. Estimated Debris - Wind Only Analysis— Category 3 Hurricane ................................... 11-51 FIGURES Figure 11-1. Tropical Storm Stages of Development: Weakest (left), with Only Basic Circular Shape; Stronger (top right) with Spiral Banding and Increased Centralization; Strongest (lower right) with an Eye ................................................................................................................................................................. 11-2 Figure 11-2. North Shore SLOSH Inundation Areas ............................................................................... 11-5 Figure 11-3. Boston SLOSH Inundation Areas ....................................................................................... 11-6 Figure 11-4. South Shore SLOSH Inundation Areas ............................................................................... 11-7 Figure 11-5. South Coastal SLOSH Inundation Areas ............................................................................ 11-8 Figure 11-6. Upper and Mid Cape Cod SLOSH Inundation Areas ......................................................... 11-8 Figure 11-7. Lower Cape Cod SLOSH Inundation Areas ....................................................................... 11-9 Figure 11-8. Dukes and Nantucket Counties SLOSH Inundation Areas ............................................... 11-10 Figure 11-9 Historical North Atlantic Tropical Cyclone Tracks (1851-2011), Northeastern U.S. ........ 11-11 Figure 11-10. Historical North Atlantic Tropical Cyclone Tracks (1851-2011), Massachusetts Vicinity 11- 11 Figure 11-11. 1938 Hurricane Track, September 10 – September 22.................................................... 11-14 Figure 11-12. Hurricane Gloria Track, September 16 – October 2, 1985 .............................................. 11-16 Figure 11-13. Hurricane Irene Storm Track ........................................................................................... 11-18 Figure 11-14. Number of Hurricanes for a 100-year Return Period: Light Blue Area, 20 to 40; Dark Blue Area, 40 to 60; Red Area, More Than 60 ............................................................................................... 11-19 Figure 11-15. Probability of a Hurricane or Tropical Storm across Massachusetts (Circled) ............... 11-20 Figure 11-16. Probability of a Category 3, 4, or 5 Hurricane (Massachusetts Circled) ......................... 11-22 11-2 Commonwealth of Massachusetts 2013 State Hazard Mitigation Plan Figure 11-17. North Shore SLOSH Inundation for a Category 4 Event ................................................ 11-35 Figure 11-18. Boston SLOSH Inundation for a Category 4 Event ........................................................ 11-36 Figure 11-19. South Shore