This research estimated the spatial-temporal patterns of tornadoes in the continental United States from 1950-2019 using the National Weather Service Storm Prediction Center’s Severe Weather GIS (SVRGIS) database. This study employed Space-Time Cube Analysis and Linear Kernel Density (Kernel Density Linear Process, (KDLP)) rather than the standard Kernel Density Estimation (KDE) approach; to evaluate whether tornado hotspot locations and intensities shift over time. The first phase of the study utilized KDLP to map changes in tornado hotspots and qualitatively assess decadal shifts in hotspot locations and intensities by occurrence and magnitude between decades using ArcGIS Pro and CrimeStat. Next an Emerging Hot Spot Analysis (EHSA) was employed to identify the changes in tornado occurrence and magnitude. ESHA results identified, by both occurrence and magnitude, significant intensifying hot spots in the Southeast region and diminishing hot spots in the Great Plains indicating an east-south-east shift.

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This thesis explores the relationship between surface elevation roughness and tornado frequency throughout the eastern United States. It builds upon previous studies which demonstrated a negative relationship between roughness and tornado frequency for the Great Plains and Arkansas. A generalized linear model with tornado frequency as the response variable and roughness and population density as the predictors is generated. This model demonstrates that increased roughness is associated with decreased tornado frequency at the scale of the entire eastern United States, especially where roughness is greater than 20 meters. The methods are also performed for 13 smaller regions within the eastern US, but an effect of roughness is only confirmed for the regions encompassing the Great Lakes and central Appalachians. From these results, it is concluded that mountain ranges, where roughness exceeds 20 meters, clearly inhibit tornado activity, but there is little evidence that smaller terrain variations have the same effect.

Between 2011-2021, violent tornadoes accounted for an average of 65% of all tornado-related fatalities. The Violent Tornado Parameter (VTP), created in 2018, attempts to address this forecast problem but has issues with false alarms. Storm Relative Helicity has historically been used in tornado forecasting. Recent studies have shown the 0-500 m effective layer SRH (ESRH) has skill in discerning significantly tornadic events from those that are not. This study explored the effects of incorporating 0-500 m ESRH into the VTP and issues relating to the parameter’s false alarm rate by examining RUC/RAP forecast soundings for 302 U.S. tornadic events (83 violent, 122 strong, 97 weak) from 2011 to 2020, along with test data from 2021. Overall, the study found that 0-500 m ESRH has skill in forecasting violent tornadoes, and that both the 0-3 km MLCAPE and 0-3 km Lapse Rate terms raised the parameter’s false alarm rate.

Tornado intensity and impacts vary drastically across space, thus spatial and statistical analyses were used to identify patterns of tornado severity in the Southeastern United States and to assess the vulnerability and estimated recurrence of tornadic activity. Records from the Storm Prediction Center's tornado database (1950-2014) were used to estimate kernel density to identify areas of high and low tornado frequency at both the regional- and state-scales. Return periods (2-year, 5-year, 10-year, 25-year, 50-year, and 100-year) were calculated at both scales as well using a composite score that included EF-scale magnitude, injury counts, and fatality counts. Results showed that the highest density of tornadoes occur in Alabama, Mississippi, and Arkansas, while the highest return period intensities occur in Alabama and Mississippi. Scaledependent analysis revealed finer details of density and intensity for each state. Better communication of high hazard areas and integration into existing mitigation plans is suggested.

Tornadoes are occurring with increased frequency in Oklahoma. Emergency preparedness planning is essential to decreasing individuals' risks of injury or death from a tornado. Research on immigrant Hispanics' knowledge and perceptions of emergency preparedness is limited. The purpose of this study was to explore the perceptions and lived experiences of immigrant Hispanics who had experienced a tornado or other crisis weather conditions in Oklahoma during spring of 2013. The research questions explored their perceived risk for injury and knowledge of tornado preparedness planning. The health belief model provided the theoretical underpinnings for this qualitative phenomenological study. Semi structured interviews were conducted with a purposeful sample of 10 immigrant individuals living in and around Oklahoma City, Oklahoma. Data were subjected to triangulation and analyzed to identify themes and patterns. Findings indicated that immigrant participants had experienced multiple tornadoes, routinely sought shelter during a tornado, and 50% had created a family emergency plan and supply kit because of their experience with tornadoes and perceived risk for injury. Identified barriers to preparedness planning were language barriers and lack of information on natural disaster preparedness. Recommendations included conducting public health outreach and establishing multidisciplinary partnerships within communities to provide cultural and linguistically appropriate disaster preparedness information to immigrant individuals. Findings provide public health practitioners with the ability to improve access and dissemination of preparedness planning information that may promote positive social change by decreasing immigrants' risk of injury and death.

The hazards literature has identified many factors as being influential in the decision making process during high risk, short-notice disasters. Risk perception and previous disaster experience are commonly identified as two of the more influential factors in this complex process. However, few studies adequately address the complex role(s) that these factors play in self-protective decision-making during successive high-risk events. In particular, the role of previous disaster experience during subsequent events is still a matter of considerable discussion and inconsistent findings. This thesis examines two events that occurred in August, 2011 in Goderich, Ontario: an F-3 tornado that struck the community on August 21st and a tornado warning that was posted for the region three days later on August 24th. This case study provided the opportunity to examine the roles of risk perception and previous disaster experience in the decision-making process during successive high-risk events. Semi-structured interviews (n=35) and close-ended questionnaires (n=268) were conducted to learn about the ways that individuals obtained and understood risk information, and to explore whether and how such information guided protective behaviors during the two events. The interviews were analyzed using thematic coding to identify response patterns, and the questionnaires were analyzed using IBM SPSS software. It was found that a sizable portion of the sample population took protective actions on August 24th in ways that were inconsistent with their actions on August 21st. Also, a significant portion of respondents chose not to take any form of protective action on August 24th despite having previously experienced the damaging tornado. The findings of this research suggest that the significance of previous disaster experience in the decision-making process is highly variable and context-dependent. A second significant research finding involves the impact of the tornado on the place attachments of Goderich residents. It was found that the disaster had significant impacts, both positive and negative, on participants' sense of place. These findings have implications for both short- and long-term disaster recovery.

The hazards literature has identified many factors as being influential in the decision making process during high risk, short-notice disasters. Risk perception and previous disaster experience are commonly identified as two of the more influential factors in this complex process. However, few studies adequately address the complex role(s) that these factors play in self-protective decision-making during successive high-risk events. In particular, the role of previous disaster experience during subsequent events is still a matter of considerable discussion and inconsistent findings. This thesis examines two events that occurred in August, 2011 in Goderich, Ontario: an F-3 tornado that struck the community on August 21st and a tornado warning that was posted for the region three days later on August 24th. This case study provided the opportunity to examine the roles of risk perception and previous disaster experience in the decision-making process during successive high-risk events. Semi-structured interviews (n=35) and close-ended questionnaires (n=268) were conducted to learn about the ways that individuals obtained and understood risk information, and to explore whether and how such information guided protective behaviors during the two events. The interviews were analyzed using thematic coding to identify response patterns, and the questionnaires were analyzed using IBM SPSS software. It was found that a sizable portion of the sample population took protective actions on August 24th in ways that were inconsistent with their actions on August 21st. Also, a significant portion of respondents chose not to take any form of protective action on August 24th despite having previously experienced the damaging tornado. The findings of this research suggest that the significance of previous disaster experience in the decision-making process is highly variable and context-dependent. A second significant research finding involves the impact of the tornado on the place attachments of Goderich residents. It was found that the disaster had significant impacts, both positive and negative, on participants' sense of place. These findings have implications for both short- and long-term disaster recovery.

The primary purpose of this research program is to confirm the spontaneous planning behavior in post-disaster operations while at the same time contribute to the development of the concept in a tornado type disaster. An additional goal also includes examining how the process takes place in resolving unanticipated problems as a disaster unfolds. This study uses qualitative methodology which is case study to probe the concept of spontaneous planning behavior to solve unexpected challenges as a disaster develops. Specifically, semi-structured, open-ended questions were utilized to collect data from stakeholders in eleven functional organizations in three impacted cities during the North Texas April 3, 2012, tornadoes. Findings indicate that debris removal and ensuring public safety, search and rescue, securing damaged neighborhoods, activation of emergency operations centers, damage assessment, restoration of communication system, public relations and media, and volunteer and donation management activities appear to have benefited from spontaneous planning behavior. Further findings suggest that the driving forces behind the phenomenon were gathering valuable new information, learning opportunity within the disaster, relative freedom and significant high degree of discretion, response was innovative with flexibility, and solutions waiting for problems features proposed in the integrated decision-making model (IDMM). However, it was uncovered that interview respondents’ answers tend to indicate that mixed organizational structures helped in problem resolutions rather than just flat organizational structure as some decision making literature may suggest. Analysis of this decision-making model expanded the understanding of how spontaneous planning behavior took place in resolving unforeseen problems in post-disaster operations. This research project confirmed the concept of spontaneous planning in the North Texas tornadoes as well as suggesting how it occurred. The research program validates spontaneous planning behavior in tornadoes; advances and develops the concept of spontaneous planning; increases understanding, description, and management of post-disaster operations; improves emergency management operations; promotes spontaneous planning as a key principle among responders and others involved in emergency management; and proposes IDMM as a useful model that explains decision-making behavior during a disaster.

No description available.