
Thomas CovaUniversity of Utah | UOU · Department of Geography
Thomas Cova
Ph.D. Geography, UC Santa Barbara
About
78
Publications
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Introduction
I'm a Professor of Geography at the University of Utah in Salt Lake City. My research and teaching interests are environmental hazards, emergency management, transportation, and geographic information science (GIS) with a focus on wildfire evacuation modeling, analysis, and planning.
Additional affiliations
January 1999 - present
Publications
Publications (78)
Description
Geographical Information Systems is a computer system used to capture, store, analyze and display information related to positions on the Earth’s surface. It has the ability to show multiple types of information on multiple geographical locations in a single map, enabling users to assess patterns and relationships between different info...
Determining the most effective public warnings to issue during a hazardous environmental event is a complex problem. Three primary questions need to be answered: Who should take protective action? What is the best action? and When should this action be initiated? Warning triggers provide a proactive means for emergency managers to simultaneously an...
Importance
Understanding exposure to air pollution is important to public health, and disparities in the spatial distribution of regulatory air quality monitors could lead to exposure misclassification bias.
Objective
To determine whether racial and ethnic disparities exist in Environmental Protection Agency (EPA) regulatory air quality monitor lo...
We analyzed the global disaster resilience research literature to advance understanding of its geographical context. A key objective was to map the variation in disaster research resilience activity to identify hotspots and areas of less activity. The motivation is to reveal regional imbalances in resilience research and collaboration to contribute...
Vulnerable populations (e.g., populations with lower income or disabilities) are disproportionately impacted by natural hazards like wildfires. It is crucial to develop equitable and effective evacuation strategies to meet their unique needs. While existing studies offer valuable insights, we need to improve our understanding of how vulnerabilities...
Effective wildfire evacuation planning requires understanding where evacuees are likely to travel and temporarily reside. Detailed information on evacuee destinations is a valuable input into critical decisions related to evacuation traffic control, shelter assignment, and return-entry planning. To improve our understanding of where evacuees stay,...
Earthquakes pose substantial threats to communities worldwide. Understanding how people respond to the fast-changing environment during earthquakes is crucial for reducing risks and saving lives.This study aims to study people’s protective action decision-making in earthquakes by leveraging explainable machine learning and video data. Specifically,...
Climate change is increasing the threat of wildfires to populated areas, especially those within the wildland-urban interface (WUI). The 2021 Marshall fire forced the evacuation of over 30,000 people in Boulder, Jeffer-son and Adams Counties in Colorado, US. To improve our understanding of wildfire evacuation response, we surveyed individuals affec...
Floods have a devastating impact on developing nations. The focus of current resilience models is predominantly developed countries, and less is known regarding how they might perform in other contexts. This paper presents a comparative case study in Bangladesh using two established hazard resilience models: the Disaster Resilience of Place (DROP)...
When evacuation is necessary in a wildfire event, affected communities must be alerted and warned of the imminent danger and instructed on what to do to protect themselves. One channel available to message providers in the United States is Wireless Emergency Alerts (WEAs) disseminated via IPAWS. Recent wildfire events have shed light on the need to...
To develop effective wildfire evacuation plans, it is crucial to study evacuation decision-making and identify the factors affecting individuals' choices. Statistic models (e.g., logistic regression) are widely used in the literature to predict household evacuation decisions, while the potential of machine learning models has not been fully explore...
As the threat of wildfire increases, it is imperative to enhance the understanding of household evacuation behavior and movements. Mobile GPS data provide a unique opportunity for studying evacuation routing behavior with high ecological validity, but there are little publicly available data. We generated a highway vehicle routing dataset derived f...
The threat of wildfires is increasing at an alarming rate due to climate change and the expansion of the wildland-urban interface. It is critical to improve understanding of people’s evacuation decisions during wildfire emergencies. Therefore, this study proposes a novel methodology to model evacuation rates using large-scale GPS data generated by...
Over the past few years early earthquake warning systems have been incorporated into earthquake preparation efforts in many locations around the globe. These systems provide an excellent opportunity for advanced warning of ground shaking and other hazards associated with earthquakes. This study aims to optimize this advanced warning for individuals...
Recently, wildfires have created severe challenges for fire and emergency services and communities in the wildland-urban interface (WUI). To reduce wildfire risk and enhance the safety of WUI communities, improving our understanding of wildfire evacuation is a pressing need. This study proposes a new methodology to analyze wildfire evacuation by le...
Developing effective recovery plans requires an intricate understanding of the experiences of affected residents following a disaster event. We combined a self-organizing map (SOM) and hierarchical clustering to analyze community perceptions towards disaster response/recovery operations following the 2015 Nepal earthquake. A survey was conducted by...
With increased frequency and intensity due to climate change, wildfires have become a growing global concern. This creates severe challenges for fire and emergency services as well as communities in the wildland-urban interface (WUI). To reduce wildfire risk and enhance the safety of WUI communities, improving our understanding of wildfire evacuati...
Hurricanes can have a significant impact on the functioning and capacity of healthcare systems. However, little work has been done to understand the extent to which hurricanes influence local residents’ spatial access to healthcare. Our study evaluates the change in spatial access to primary care physicians (PCPs) between 2016 and 2018 (i.e., befor...
Recent extreme wildfires are motivating unprecedented evacuation planning. A critical need is to consider dire scenarios that allow less time to clear an area than required. Although these scenarios often begin with an ignition near a community, any scenario can become dire due to weather conditions, human response, technology, cascading events, an...
Purpose
Return-entry is understudied in the disaster science literature. This paper provides an overview of the return-entry process, identifies key factors informing the selection of return strategy, proposes a simple classification of return strategies and offers ideas for advancing research in this area.
Design/methodology/approach
This paper e...
The aim of this paper is to advance understanding of the value of national address point databases in improving wildfire public safety in the U.S. The paper begins with a review of the value of a national address point database in wildfire evacuations. An introduction to address point data in the U.S. is presented by examining two national address...
Wildfire evacuation triggers refer to prominent geographic features used in wildfire evacuation practices, and when a fire crosses a feature, an evacuation warning is issued to the communities or firefighters in the path of the fire. The existing wildfire trigger modeling methods consider evacuation time as an input from a decision maker and employ...
Determining the most effective public warnings to issue during a hazardous environmental event is a complex problem. Three primary questions need to be answered:Who should take protective action? What is the best action? andWhen should this action be initiated? Warning triggers provide a proactive means for emergency managers to simultaneously answ...
Data models describe how reality is to be represented in a database. Geographic data models are data models that incorporate an explicit representation of geographic phenomena. Two conceptual perspectives used in geographic data modeling involve viewing geographic reality as comprising continuous fields or discrete geographic objects, otherwise kno...
Determining household earthquake risk perceptions and adjustments is important for improving our understanding of community preparedness and establishing baselines fro improvements. Greater than 90% of the Utah population lives within 25 km of the Wasatch Fault System (WFS), and a 2012 FEMA report ranked seismic risk in Utah as the 6th highest in t...
Wildfire evacuation triggers are prominent geographic features used in wildfire evacuation practices to facilitate warning and communication during evacuations. When a fire crosses these features, emergency managers issue evacuation orders for the residents in the path of the fire. Computerized modeling of triggers uses geographic information syste...
The Social Vulnerability Index (SoVI) has served the hazards community well for more than a decade. Using Utah as a test case, a state with a population exposed to a variety of hazards, this study sought to build upon the SoVI approach by augmenting it with a non-linear Artificial Neural Network (ANN). A SoVI was created for the state of Utah at th...
Decision making in complex environments has been investigated in many domains, including medicine, aviation, business, and police operations. However, how incident commanders (ICs) make protective-action recommendations (PARs) to populations exposed to wildfire risks is underinvestigated. In this study we examined the effect of expertise on IC non-...
Each year wildfire incident commanders (ICs) manage thousands of events throughout the USA that often threaten life and property. In this task they make important decisions to protect both firefighters and citizens, usually under time pressure and uncertainty. Many environmental factors affect the choice and timing of the most effective protective-...
Communicating risk to evacuated populations is challenging for emergency officials during the return-entry phase. Although decades of research focused on understanding relationships between risk communication and evacuation behavior, very little has been done to understand risk communication and return-entry behavior. This research examines risk co...
Residential development in fire-prone areas of the western United States is a growing concern. The steady addition of homes to this region places more people and property at risk each year. In many areas housing is increasing without commensurate improvements in the road network, particularly in regards to the number, capacity and arrangement of co...
Wildland firefighters are often called on to make tactical decisions under stressful conditions in order to suppress a fire. These decisions can be hindered by human factors such as insufficient knowledge of surroundings and conditions, lack of experience, overextension of resources or loss of situational awareness. One potential tool for assisting...
Developing effective evacuation and return-entry plans requires understanding the spatial and temporal dimensions of risk perception experienced by evacuees throughout a disaster event. Using data gathered from the 2008 Cedar Rapids, Iowa Flood, this article explores how risk perception and location influence evacuee behavior during the evacuation...
Improving community resiliency to wildfire is a challenging problem in the face of ongoing development in fire-prone regions. Evacuation and shelter-in-place are the primary options for reducing wildfire casualties, but it can be difficult to determine which option offers the most protection in urgent scenarios. Although guidelines and policies hav...
There is an increasing need for a quick, simple method to represent diurnal population change in metropolitan areas for effective emergency management and risk analysis. Many geographic studies rely on decennial U.S. Census data that assume that urban populations are static in space and time. This has obvious limitations in the context of dynamic g...
This paper proposes an explicit set of constraints as a general approach to the contiguity problem in site search modeling. Site search models address the challenging problem of identifying the best area in a study region for a particular land use, given that there are no candidate sites. Criteria that commonly arise in a search include a site's ar...
Contemporary GIS can handle static spatial data for querying and visual representation, but the temporal dimension remains a challenge. This paper addresses the need for a dynamic GIS capable of managing complex data types. The design relies on a representation of the theoretical spatiotemporal primitive known as the ‘geo-atom’. This paper proposes...
Aims Sin Nombre virus (SNV), a strain of hantavirus, causes hantavirus pulmonary syndrome (HPS) in humans, a deadly disease with high mortality rate (> 50%). The primary virus host is the deer mouse, and greater abundance of deer mice has been shown to increase the human risk of HPS. Our aim is to identify and compare vegetation indices and associa...
Despite threats posed to communities from wildfire, few tools exist to aid emergency managers in recommending evacuations. An evacuation trigger buffer is a pre-established boundary encompassing a community or asset that triggers an evacuation recommendation should a fire cross the edge of the buffer. The Wildland–Urban Interface Evacuation model (...
Earthquake loss estimation studies using the HAZUS-MH Earthquake Model favor county and tract-based analyses. The goal of this research is a parcel-scale study of Salt Lake County capable of providing loss estimates for individual homeowners. This can be achieved by leveraging the methodology of the HAZUS-MH Advanced Engineering Building Module (AE...
The decision of whether to evacuate or shelter-in-place SIP in a wildfire poses a significant challenge for emergency managers and residents in fire-prone areas. Events such as the 2007 Witch Creek Fire and 2008 Tea Fire in California highlight the option and viability of SIP, as well as the conflict that can occur between first-responders and resi...
Incorporating the temporal element into traditional GIS is a challenge that has been researched for many years and has many proposed solutions. The implemented system “Extended Dynamic GIS” or EDGIS is based on the “geo-atom” and Space Time Point (STP). EDGIS provides a platform for spatiotemporal data representation, storage, and query in order to...
Return-entry is the movement of an evacuated population back to an area following the issuance of an all-clear message. This research examines the geographic, communication, and demographic factors that affect return-entry compliance rates using Hurricane Rita 2005 as a case study. Surveys were mailed to 1,200 households in a twelve county area com...
This book constitutes the refereed proceedings of the 5th International Conference on Geographic Information Secience, GIScience 2008, held in Park City, UT, USA, in September 2008.
The 24 revised full papers presented were carefully reviewed and selected from 77 submissions. Among the traditional topics addressed are spatial relations, geographic...
Data concerning dynamic geographic processes are commonly captured and stored as discrete temporal snapshots. Snapshot data often require interpolation to compensate for large data collection intervals. Metamorphosis (morphing or tweening) is the study of how an object changes over time. Tweening was developed to perform basic transformations rathe...
An evacuation trigger is a point on the landscape that, once crossed by a wildfire, triggers an evacuation for a community.
The Wildland-Urban Interface Evacuation (WUIVAC) model can be used to create evacuation trigger buffers around a community
using fuels, weather, and topographic inputs. A strategic, community-scale application of WUIVAC for th...
Volcanic ash can cause physical damage to an aircraft to the point of mechanical and electrical malfunction. In the event of an ash plume, aircraft would likely be diverted or grounded, leading to economic losses. This article presents two indices to compare the economic vulnerability of flight paths to volcanic ash plumes. The first index includes...
Geographic representation has become more complex through time as researchers have added new concepts, leading to apparently endless proliferation and creating a need for simplification. We show that many of these concepts can be derived from a single foundation that we term the atomic form of geographic information. The familiar concepts of contin...
A quick search of “exurbia” on the internet yields various definitions: ‘the region outside the suburbs of a city, consisting of residential areas (exurbs) that are occupied predominantly by rich commuters (exurbanites) (www.wordreference.com/English); and the cryptically self‐referential ‘a typically exurban area’ (www.bartleby.com). Nighttime sat...
This paper examines the timing of protective action recommendations in relationship to the distance of wildfire to a threatened community using exploratory map animation. The 2003 Southern California Wildfires were animated to assist in understanding the complex interaction between fire progression and warnings to threatened communities. Explorator...
Warning communities in the path of an advancing wildfire is a challenging problem. Decision makers need the most current information available to determine who should evacuate, when they should leave and what type of order to issue (e.g. mandatory, recommended, voluntary). This paper presents a new method for delimiting wildfire evacuation trigger...
Residential development in fire-prone wildlands is a growing problem for land-use and emergency planners. In many areas housing is increasing without commensurate improvement in the primary road network. This compromises public safety, as minimum evacuation times are climbing in tandem with vegetation and structural fuels. Current evacuation codes...
Fire-prone landscapes are increasingly being settled. Monitoring this development is an emerging need, and a low-cost method would benefit emergency managers. Existing change-detection methods can be expensive and time consuming when applied to low-density urban change in large, vegetated areas. Nighttime satellite imagery is explored as means for...
Most traffic delays in regional evacuations occur at intersections. Lane-based routing is one strategy for reducing these delays. This paper presents a network flow model for identifying optimal lane-based evacuation routing plans in a complex road network. The model is an integer extension of the minimum-cost flow problem. It can be used to genera...
Residential development in fire-prone wildlands is occurring at an unprecedented rate. Community-based evacuation planning in many areas is an emerging need. In this paper we present a method for using microscopic traffic simulation to develop and test neighborhood evacuation plans in the urban - wildland interface. The method allows an analyst to...
This paper describes a means for linking field and object representa-tions of geographical space. The approach is based on a series of mappings, where locations in a continuous eld are mapped to discrete objects. An object in this context is a modeler's conceptualization, as in a viewshed, highway corridor or biological reserve. An object can be re...
This paper describes the structure of a large multi-institutional
consortium to perform research in the use of remote sensing and
geospatial analysis to transportation hazard assessment and management.
After discussing the focus of the research consortium, research at
individual centers is considered
This paper proposes an explicit set of constraints as a general approach to the contiguity problem in site search modeling. Site search models address the challenging problem of identifying the best area in a study region for a particular land use, given that there are no candidate sites. Criteria that commonly arise in a search include a site's ar...
Simultaneously locating and configuring the best site for a given land use or activity is a complex planning problem. This paper describes a method for addressing this problem that relies on a point-to-area neighborhood operator applied to a raster model of geographic space. This represents a synthesis of concepts drawn from cartographic modeling,...
this paper is to describe a class of geographic data model that combines elements of the field and object models of space. The class is based on the concept of a field of spatial objects, where every location in a field is associated with a geo-referenced object, or set of objects. In this context, an object is a modeler's conceptualization, like a...
The focus of this paper is on the development of a methodology to identify network and demographic characteristics on real transportation networks which may lead to significant problems in evacuation during some extreme event, like a wildfire or hazardous material spill. We present an optimization model, called the critical cluster model, that can...
This chapter examines the role of GIS in emergency management through the lens of comprehensive emergency management (CEM) and its four phases: mitigation, preparedness, response, and recovery. The primary concern before a potential disaster is mitigating the impact of a hazard. Here GIS is gaining favour in risk assessment and the development of l...