Section 4: Risk Assessment
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Section 4: Risk Assessment [The risk assessment shall include a] description of the type, location and Requirement extent of all natural hazards that can affect the jurisdiction. The plan §201.6(c)(2)(i): shall include information on previous occurrences of hazard events and on the probability of future hazard events. [The risk assessment shall include a] description of the jurisdiction's vulnerability to the hazards described in paragraph (c)(2)(i) of this Requirement section. This description shall include an overall summary of each hazard §201.6(c)(2)(ii): and its impact on the community. All plans approved after October 1, 2009 must also address NFIP insured structures that have been repetitively damaged by floods. For multi-jurisdictional plans, the risk assessment must assess each Requirement jurisdiction's risks where they vary from the risks facing the entire §201.6(c)(2)(iii): planning area. Risk assessment is a process of estimating the potential for injury, death, property damage, or economic loss which may result from a hazard. A risk assessment is only as valuable as the thoroughness and accuracy of the information on which it is based. As will be seen, there is a great variation between hazards in the amount and reliability of the data available for analysis. Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 101 Identification of Hazards The following natural hazards have been identified as posing potential risk in the planning area: Severe Winter Weather (Snow, Ice, and Extreme Cold) Severe Thunderstorms (includes Damaging Winds, Hail, and Lightning) Tornado Flood (includes riverine flooding, flash flooding, and storm water flooding) Levee Failure Dam Failure Extreme Heat Drought Wildfire Earthquake Land Subsidence/Sinkhole The Missouri State Hazard Mitigation Plan (2013) indicates that expansive soils, landslides, and rockfalls are recognized as hazards in Missouri but occur infrequently and with minimal impact. For this reason, those hazards were not profiled in the state plan nor will they be profiled in the Cole County/Jefferson City Plan. There are certain other natural hazards which FEMA requires to be addressed in Hazard Mitigation Plans if they are applicable to the planning area. Avalanches and volcanoes have not been included in this plan as they do not pose a threat due to Cole County’s topography and geology. Coastal erosion, coastal storms, hurricanes, and tsunamis do not pose a threat to the county due to its inland location. In addition to natural hazards, the following technological/human hazards have been identified as posing potential risk in Cole County and are profiled in this plan in Section 5: Public Health Emergency Hazardous Materials Release Transportation Incident Nuclear Incident Utility Service Disruption Cyber Attack Armed Intruder Terrorism Civil Disorder Mass Casualty/Fatality Event Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 102 Risk Assessments for Identified Hazards A Risk Assessment has been conducted for each hazard identified as affecting the planning area. The remainder of this section includes these risk assessments which are organized according to the following outline: DESCRIPTION OF HAZARD Location Extent - The extent of the hazard refers to the strength or magnitude of that hazard which can be expected in the planning area; extent is an attribute of the hazard alone and does not include its effect on humans or the built environment. Previous Occurrences Probability of Future Events (Natural Hazards) - The probability of future events is, for the most part, based on historical data while also taking into account the expected impact of climate change. It is assigned based on the following scale which was slightly modified from that found in the Missouri State Hazard Mitigation Plan (2013): Low – The hazard has little or no chance of happening (less than 1 percent chance of occurrence in any given year) Moderate – The hazard has a reasonable probability of occurring (between 1 and 10 percent chance of occurrence in any given year). High – The probability is considered sufficiently high to assume that the event will occur (between 10 and 100 percent chance of occurrence in any given year). In the case of earthquakes, projections made by the USGS have also been taken into account in assessing the probability. Probability of Future Events (Technological/Human-made Hazards) – There is a lack of historical data for most of the technological/human-made hazards profiled; in addition, some of them are evolving on a monthly basis as political and cultural events play a large role in some of the hazards. For at least one technological/human-made hazard for which historical is available (hazardous materials release), the probability calculated using the same scale as used for natural hazards was considered ridiculous by those working closely with this hazard. (The calculated probability would have been high.) Representatives of the LEPC indicated that seeing a “high” probability associated with this hazard would make them question the validity of the entire hazard mitigation plan. So, for these reasons, the probability of technological/human-made hazards was evaluated and assessed by those working most closely with these hazards in some emergency management or preparedness capacity. Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 103 IDENTIFICATION OF COMMUNITY ASSETS potentially affected by or helping to mitigate the effects of the hazard in each participating jurisdiction; this is covered in Section 2 of the plan. ANALYSIS OF RISK presented by the hazard, including a measure of severity for each participating jurisdiction. The measure of severity is an estimate of the deaths, injuries, or damage (property or environmental) that could result from the hazard. It is also broadly based on the scale found in the Missouri State Hazard Mitigation Plan (2013): Low – Few or minor damage or injuries are likely. Moderate – Personal injuries and/or damage to property or the environment are expected. High – Major injuries and/or death and/or major damage will likely occur. SUMMARY OF VULNERABILITY A jurisdiction’s vulnerability to a hazard is connected to the extent of that hazard, the probability of future events, the estimated measure of severity, and mitigation measures already in place for that hazard. In many cases, the potential severity of the hazard event contributes the greatest weight to the vulnerability rating. In some cases, however, a low severity event with high frequency can cause economic strain which translates into a higher vulnerability. Existing Mitigation/Operating Assumptions: Both the measure of severity and overall vulnerability are greatly impacted by the mitigation already in place in the planning area; this existing mitigation is taken as an operating assumption when evaluating the vulnerability to a particular hazard. The following mitigation activities are applicable to many or all hazards: Building codes are in place in Cole County, Jefferson City, Russellville, St. Martins, St. Thomas, Taos and Wardsville. Cole County and Jefferson City have alternate methods/locations in place for fueling emergency vehicles. Interconnections are in place between Missouri American Water and PWDS #1 and PWSD#2.. Buses in all school districts have two-way radios on board. Agreements are in place with local shelters in the planning area. General evacuation procedures are included in the Office of Emergency Management’s (OEM) Emergency Operation Plan. Other current mitigation activities are aimed at mitigating the effects of a specific hazard and are described under the specific hazard profile. Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 104 THE EFFECTS OF CLIMATE CHANGE ON HAZARDS While climate change remains a contentious political issue in the United States, the scientific data is overwhelmingly clear – the climate is changing. The Cole County Hazard Mitigation Planning Committee deemed it important to include a consideration of the effect of climate change on the hazards profiled. This is not required for the county level plans but, as of March 2016, will be required for state hazard mitigation plans. The information for this section is taken primarily from The National Climate Assessment 2014. The 2014 assessment was put together by a team of 300 experts under the guidance of a 60- member Federal Advisory Committee. The assessment was reviewed by the public and other experts in the field, including the federal agencies and a panel from the National Academy of Sciences. The full report can be accessed at: GlobalChange.gov. A number of charts from The National Climate Assessment 2014 have been included to indicate just some of the scientific data supporting the conclusion that the climate is changing. Global temperatures show a sharp increase which correlates with the increasing CO2 concentration in the atmosphere (Figure 4.1). Figure 4.1 Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 105 There has been a significant increase in frost-free days across the continental U.S. in the past two decades when compared with the average for the period 1901-1961 (Figure 4.2). Figure 4.2 Likewise, there has been a trend of increased cooling demand in the past two decades (Figure 4.3). Figure 4.3 Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 106 There is a strong upward trend in heavy precipitation for the U.S. as a whole, beginning in the 1940s (Figure 4.4). (The horizontal line at zero represents the average precipitation for the period 1901-1960.) Figure 4.4 However, this heavier precipitation is affecting different regions of the country to varying degrees; the Northeast and the Midwest are experiencing the largest increase in sudden torrential downpours (Figure 4.5). Figure 4.5 Section 4 Cole County/Jefferson City Natural Hazard Mitigation Plan 107 The National Climate Assessment, 2014, states that the current data indicates observed increases in the following: winter storms, extreme heat, heavy downpours, and the intensity, frequency, and duration of hurricanes.