Appendix 3-1: HIRA Methodology & Reference Data A blend of quantitative factors extracted from the National Center for Environmental Information, local damage assessment data, and the 2018 Local Risk Perspective Survey, were used for the new 2018 Baltimore City Hazard Identification and Risk Assessment (HIRA). The following five (5) rating parameters were used to develop hazard risk ranking for the (15) identified sixteen hazards. Probability Probability means the likelihood of the hazard occurring and are defined in terms of general descriptors, (for example, unlikely, somewhat likely, likely, highly likely), historical frequencies, statistical probabilities, and/or hazard probability maps. Deaths Hazard related deaths correlate to the severity of impact to the community from any specific hazards. Injuries Hazard related injuries correlate to the severity of impact to the community from any specific hazards. Damages Hazard related damages include both property and crop damages and correlate to the severity of impact to the community from any specific hazards. Local Hazard Risk Perspective A local hazard risk perspective provides a basis for determining those hazards that are of concern to people who work and/or live in the planning area. Levels of concern are defined in terms of general descriptors, (for example, not concerned, somewhat concerned, concerned, very concerned). 1 Table 3-1 below provides the specific rating criteria used in this analysis. All rating criteria are equally weighted. HIRA results are presented in Table 3-2. Table 3-1: Hazard Rating Criteria Probability Rating Local Risk Perspective Damages Rating Criteria Rating Criteria Rating Criteria 1 0-0.49 events/year 1 Not Concerned 1 None Somewhat 2 0.50-1 events/year 2 2 Minor Concerned 3 1.1-2.5 events/year 3 Concerned 3 Significant 2.6 or more 4 4 Highly Concerned 4 Major events/year Deaths Injuries Rating Criteria Rating Criteria 1 None 1 None 4 1 or more 4 1 or more 2 Table 3-2: Overall Hazard Risk Ranking Hazards Injuries Deaths Ranking Damages Local Risk Probability Hazard Risk Perspective Flooding Flood 3 4 4 4 4 19 Dam Failure 1 1 1 1 2 5 Coastal Hazards Tropical Storms & Hurricanes 1 1 1 4 4 11 Storm Surge/Coastal Inundation 2 1 1 2 3 9 Sea Level Change 4 1 1 4 4 14 Tsunami 1 1 1 1 1 5 Precipitation Variability Thunderstorms (Lightning & Hail) 1 4 4 1 3 13 Winter Storms & Nor’easter 4 4 4 4 3 19 Drought 1 1 1 4 2 9 Wind Thunderstorm Winds & Derecho 4 4 4 4 3 19 Tornados 1 1 4 3 2 11 Extreme Heat Heat & Air Quality 4 4 4 1 4 17 Land Earthquakes 1 1 1 4 1 8 Landslump/Subsidence 1 1 1 1 1 5 Sinkholes 3 1 1 4 3 12 Hazard Risk Ranking Categories Low Risk Medium Risk High Risk 0-6 7-13 14-20 Note: Hazards that do not include past occurrence data were assessed for future probability. Those hazards that were assessed as having a low probability of occurrence within the planning area, indicated as a “1” on the table above, were then assessed as “1” for all other rating parameters. Those hazards included dam failure and tsunami. Those hazards assessed as probable, indicated as a “2” or higher on the table above were then assessed for all other rating parameters based upon likelihood of occurrence and associated impacts. 3 Table 3-3: HIRA Raw Data Table Hazards Deaths Injuries (Property Local Risk Damages Perspective Probability and/or Crop) Flood 3.23 5 2 1.881.03 M 3.6 Tropical Storms & Hurricanes 1.6 0 0 252.6 M 3.5 Storm Surge/Coastal Inundation 0.68 0 0 45K 3.2 Thunderstorms (Lightning & Hail) 0.36 2 1 35K 3.0 Winter Storms & Nor’Easter 7.36 3 20 1.605 M 3.2 Drought 0.45 0 0 1.67 M 2.3 Thunderstorm Winds & Derechos 2.02 1 29 8.267 M 2.7 Tornados 0.27 0 3 200K 2.2 Heat & Air Quality 2.77 68 280 0 3.5 Earthquakes 0.89 0 0 3 M 1.5 Sinkholes 1.3 0 0 2.5 Table 3-4: Local Risk Perspective Survey Hazards Local Risk Perspective Survey Results Flooding Flood Very Concerned Dam Failure Somewhat Concerned Coastal Hazards Tropical Storms & Hurricanes Very Concerned Storm Surge/Coastal Inundation Concerned Sea Level Change Very Concerned Tsunami Not Concerned Precipitation Variability Thunderstorms (Lightning & Hail) Concerned Winter Storms & Nor’Easter Concerned Drought Somewhat Concerned Wind Thunderstorm Winds & Derecho Concerned Tornados Somewhat Concerned Extreme Heat Heat & Air Quality Very Concerned Land Earthquakes Not Concerned Land slump/Subsidence Not Concerned Sinkholes Concerned 4 Table 3-5: High Risk Hazards Local Hazard Risk Hira Results Perspective Flood Flood Tropical Storm/Hurricane Sea Level Change Sea Level Change Winter Storm Heat & Air Quality Thunderstorm Winds & Derecho Heat & Air Quality Note: Those hazards shown in bold text denote hazards rating as “high” risk in both the local hazard risk assessment & the HIRA. 5 HIRA Data Sources Table 3-6: HIRA Data Sources National Center for Date Range Other Data Hazard Environmental (Best Available Data- Sources Information Data Range Varies) Flood Flash Floods Baltimore Sun 1996-March 2018 Flood Heavy Rain Dam Failure No Data Available MDE Dam Safety N/A Tropical Storms & Hurricane Baltimore Business 1999-March 2018 Hurricanes Tropical Storm Journal NOAA National Weather Service Storm Surge/Coastal Storm Surge/Tide Coastal Baltimore Sun 1999-March 2018 Inundation Flood The Washington Post Chesapeake Quarterly Sea Level Change No Data Available Baltimore Sun N/A Chesapeake Quarterly Sea Grant Maryland Yale Climate Connections Tsunami No Data Available National Geophysical N/A Data Center Extinction Theory Thunderstorms Lightning Baltimore Sun 1957-March 2018 (Lightning & Hail) Hail Winter Storms & Nor’Easter Winter Weather Baltimore Sun 1996-March 2018 Winter Storm Ice Storm Blizzard Heavy Snow Frost/Freeze Cold/Windchill Drought Drought MDE- MD Drought 1998-2017 Status Thunderstorm Winds & Thunderstorm Wind High Baltimore Sun 1957-March 2018 Derecho Winds Strong Winds Tornados Tornado Baltimore Sun 1996-March 2018 Funnel Clouds Baltimore Patch Heat & Air Quality Excessive Heat Baltimore Sun 1996-2017 Heat Earthquakes No Data Available Baltimore Sun 1962-2017 Earthquaketrack.com WMAR Land No Data Available Maryland Geological N/A Slump/Subsidence Survey Sinkholes No Data Available Baltimore City DPW 2008-2016 Baltimore Sun 6 National Center for Environmental Information (NCEI) Data Table 3-7: Blizzard Events (January 7, 1996-March 31, 2018) Property Date Area Narrative Deaths Injuries Damage An historic winter storm, known as the "Blizzard of '96", crippled all of Maryland west of the Chesapeake Bay during the first full weekend of January. In general, snow totals were 20 to 26 inches in central Maryland. To complicate matters, wind gusting in excess of 35 mph produced drifts of 4 to 7 feet, except over 10 feet in the mountains. The storm produced the larges statewide storm totals since the "Megalopolitan Storm" of February 11th, 1983. The storm was induced by a digging upper level trough over the eastern Great Plains. At the surface, an inverted trough extended from the Gulf of Mexico through the Deep South. Surface pressures began falling as the upper trough approached on the afternoon of the 7th. Meanwhile, confluent flow, behind an upper-level arctic vortex over the Canadian Maritimes, maintained strong (1034 mb) surface high pressure over northern New York state. As the upper-level trough approached the southeast U.S. on the 8th, a new surface low developed along the Georgia coast. The low deepened explosively while the arctic high remained in place. Copious Gulf of Mexico and Atlantic moisture was entrained into the system, producing heavy snow; the increasing gradient between the intensifying low and the arctic high caused winds to strengthen to 25 mph with gusts to 35 mph. The system moved slowly from South Carolina to the mouth of the Chesapeake Bay overnight on the 7th. The slow movement prolonged near-blizzard conditions into the 8th. The storm finally moved towards New England later on the 8th, ending the snow but maintaining gusty north winds (and substantial blowing and drifting snow) until evening. The storm effectively closed all major highways on the 7th, but interstates were "open" by the 8th, even though snow removal equipment fought a losing battle with the considerable blowing and drifting snow. All federal, state, January 7 – Southern and local governments were closed Monday (the 8th) and Tuesday (the 9th). Most school districts remained closed for the week. 1 0 N/A January 8, 1996 Baltimore A federal state of emergency was declared the following Friday (the 12th). Snow removal/damage costs exceeded $70 million (state and county combined), a state record for an individual winter storm. The vast majority was incurred by snow removal operations; another $3.7 million was budgeted for repairs to highways including potholes, guard rails, and side banks. A potent area of low pressure strengthened over the central portion of the nation on the fifth of February. The storm system February 5 – Southern slowly moved through the Mid-Atlantic during the night of the 5th before redeveloping off the Mid-Atlantic coast on 6th. The February 6, 2010 Baltimore storm system finally moved away from the area on the night of the 6th. - - N/A Strong high pressure continued to pump in plenty of cold air across the region for the entire event. Due to the slow movement of the storm, there was a prolonged period of precipitation. The storm system ushered in copious amounts of moisture from the Gulf of Mexico and the Atlantic Ocean.