Week 10 - mapping the station fire

Disasters, such as wildfires, are a natural part of southern California's landscape and as a state that now supports roughly 37 million people, it is essential to prepare safety measures in times of emergency.  The Station Fire in Los Angeles scorched over 160,000 acres during its proliferation, requiring over 1,000 firefighters and over two weeks to completely contain ("Station Fire Containment," 2009).  The station fire claimed two lives, destroyed many homes and buildings, and caused officials to issue both voluntary and mandatory evacuations.  With more research being conducted on the ways fires progress in regards to wind direction, elevation and vegetation, government officials and residents will be able to better predict the ways wildfires will impact the community.  This type of research has led to many questions surrounding best practices of evacuations.  In fact, it wasn't until 2001 that the national Transportation Research Board first assembled a group charged with the objective of "coordinating and disseminating evacuation-related research information (Wolshon, Urbina, Wilmot & Levitan, 2005, p.139).  According to Wolshon et. al (2005), transportation is dependent upon private automobiles and in times of emergency evacuation, it can cause major congestion problems that create challenges not only for evacuees but also for emergency management officials (p.136).  Coordination of transportation systems as well as effective communication of evacuation plans is essential in conducting effective and fast evacuation during times of emergency.

Modeling of best practice ideas of evacuations have been made possible by various tests using integer programming models, geographic information systems and current weather technology.  A study conducted by Stepanov and Smith (2009) suggests that the shortest routes does not necessarily ensure the safest evacuation; however, avoiding the over-utilization of various road segments while minimizing total clearance time and total traveled distance have demonstrated to provide population safety during the evacuation process (p. 439, 443).  The main purpose of preparing plans for potential evacuations is critical in providing decision makers with the tools they need to ensure the safety of residents and to analyze the situation properly.  For example, training is essential in determining the level of threat when it comes to evacuations as many residents may not feel the urgency to evacuate and leave their property and valuables behind unless the evacuation is mandatory, and even then, some residents would prefer to take their chances and guard their belongings.

For purposes of this study, the area would need to be under mandatory evacuation in order for the thematic map to perform appropriately.  The maps below show first, the extent of the Station Fire of 2009 over the period of a few days, and secondly a proposed plan for evacuation under wemergency conditions caused by wildfires in southern California.  The reference map displays the area of the 2009 Station Fire represented by layers of polygons showing the proliferation of the fire over the  course of a few days.  Elevation, major roads and airports are added as a reference.  The thematic map shows public transportation bus routes connected to the potential evacuation area layered on top of population density (displayed as a choropleth map) (as well as reference map features).  The purpose of this thematic map is to demonstrate a different approach to mandatory evacuation by utilizing the public transportation system as part of the plan.  The plan would need to be designed as a two phase process, allowing residents to evacuate by private automobile during an allotted time period followed by a second phase that prohibits private automobiles and clears the road for all public transportation and government vehicles to take over.  The five public transportation routes each correspond to five separate zones that residents would be already assigned to prior to the evacuation when the plan for evacuation is disseminated among residents (zones shown by yellow boxes on map, bus routes displayed by colored lines).  These separate routes permit transportation vehicles to move large amounts of people faster with a limited number of cars on the road.  The enhanced carrying capacity allows more people to evacuate by fewer vehivles while the open roads and multiple routes provide for a faster evacuation process.  Predetermined shelters (i.e. schools, convention centers, religious buildings) would be assigned to the various bus routes so that the optimum efficiency may be achieved.  Since the volume of people may not be supported by the number of vehicles available, it is critical for busses to drop off evacuees and return to the loading zone as soon as possible (allowing for drivers to change every so often at the shelter locations).

Research on specific evacuation policies reccommends an implementation mechanism that enforces evacuations by designing plans that are the least restrictive and least resource-intensive to promote efficiency under urgent demands, which indicates that a plan designed to remove cars from the road while establishing multiple exit routes may prove to be the most effective (Fairchild, A. L., Colgrove J., & Jones, M. M., 2006).  A study and experimental model conducted by Sayyady and Eksioglu (2010) argues that the transit system is an integral piece to evacuation planning as it is heavily relied upon in urban areas; in the case of studying the evacuation mechanism for Hurricane Katrina in 2005, the study noted that "15-30% of the population in New Orleans is transit dependant" (p. 488). Though the study mainly focused on transit-dependent residents, the use of fewer vehicles on multiple specific routes for all residents remaining after phase I may prove to be the optimum organization for rapid evacuation.  Lu, Huang, & Shekhar (2003) designed two models, the single route option and the multiple route option to demonstrate capacity constraints and to test the effectiveness of both and found that the multiple route option produced "close-to-optimal solution with significantly reduced computational time compared to optimal solution algorithms" although it is likely to be "more expensive since the single-route approach can produce solution for large network in seconds" (p. 112).

Though research and further modeling are essential in preparing cities and regions for natural disasters, there is an inherent unpredictability to emergency situations.  Environmental changes due to both anthropogenic (greenhouse gas emissions) and natural causes have altered climate and weather patterns and have caused more frequent and more intense disasters, such as tsunamis, floods and tornadoes.  Planning for such events enables decision makers and residents alike to prepare for such circumstances.  GIS along with other current programming and modeling technologies provide the tools for planning and it is up to engineers, urban planners and government officials to orchestrate colloquiums and research forums to further advance best practices and guidelines for evacuation planning.



Bibliography

Fairchild, A. L., Colgrove, J., & Jones, M. M. (2006). The Challenge of Mandatory Evacuation: Providing For and Deciding For. Health Affairs 25(4), 958-967

Lu, Q., Huang, Y., & Shekhar, S. (2003).  Evacuation Planning: A Capacity Constrained Routing Approach. Lecture Notes in Computer Science 959, 111-125.

Sayyady, F. & Eksioglu, S. D. (2010).  Optimizing the use of public transit system during no-notice evacuation of urban areas.  Computers & Industrial Engineering 59, 488-495.

Station Fire Containment Pushed Back to Saturday. (2009, Sept 14). Daily News Los Angeles. Retrieved from http://www.dailynews.com/news/ci_13333211.

Stepanov, A., & Smith, J. (2009).  Multi-objective evacuation routing in transportation networks. European Journal of Operational Research 198, 435-446.

Wolshon, B., Urbina, E., Wilmot, C., & Levitan, M. (2005).  Review of Policies and Practices for Hurricane Evacuation. I: Transportation Planning, Preparedness, and Response. Natural Hazards Review 6(3), 129-142. doi: 10.1061/(ASCE) 1527-6988(2005)6:3(129).