public storm shelters: a plan for norman, oklahoma · 2016-11-14 · • tornado tracks for 1950 to...

StatementofPurposeInrecentyearspublicstormsheltershavecomeunderalotofscrutiny,andmanyhavecometotheconclusiontheydomoreharmthangood.However,sincenotallresidentshaveaccesstosuitableshelter,andsafetyshouldbeabasicright,itisintheinterestofmunicipalitiestolookintoallpossibleshelteringoptions.ThisideamotivatesthisplanningstudytodeterminethecostandbenefitofapublicstormshelternetworkinthecityofNorman,Oklahoma.

Background• In2013,Norman,Oklahomacloseddownallitspublicsheltersciting

thefollowingconcerns:• Greaterriskwhiletravelling• Integrityofsheltersagainst200+mphwinds.• Overcrowding• Healthconcernsregardingpets

• Normanislocatedinahighriskareafortornadoes(seeFigure1)andhasavulnerablepopulation(Cutteretal.,2003;seeFigure2)

• Communitysheltersmaybethebestwaytokeepthepopulationsafe• Itispossibletoanswermostoftheconcernsregardingpublicshelters:• Shelterscanbeplacedwithin400mofallbuildings(5minwalk)• Sheltercapacitycanbematchedtothesurroundingpopulation• Mostmodernsheltersarecapableofwithstanding200+mphwinds

DataandMethods• DataSources• Tornadotracksfor1950to2015(SPC,2016)• NormanInteractiveMapdata(CityofNorman,2016)• Demographicdatafromthe2010Census(MPC,2016)

• Shelterlocations• Firstguesswasthecenterofa800x800mgridplacedoverNorman• Finallocationwasthemeancenterofthesurroundingbuildings.• Additionalshelterswereplacedateachschoolandhospital.

• Shelterspecifications• Capacitywasbasedonthesurroundingpopulation• CostwasbasedoncapacityusingthepriceestimatesinTable1.

• Prioritytobuildshelters• Highforschools,hospitals,ormobilehomeparks• Mediumforothervulnerablepopulations• Lowotherwise

• ThecostperlifesavedforstormshelterswasassessedfollowingthemethodofSimmonsandSutter(2006).

Discussion• Standalonestormsheltersarenoteconomical• Bestpracticesinvolvenewconstruction• FEMAcancoverupto75%ofapprovedpersonalor

communitystormshelterprojectsundertheirHazardMitigationGrantProgram(FEMA,2016a).

• Itisusuallycheapertobuildasaferoominanewbuildingthantoretrofitanoldone(FEMA,2010).

• Increasedpushforbetterconstructionshouldreducecoststhroughcompetition(Johnston,2013).

• Newhomescanwithstandwindsupto120+mphwiththeadditionofmetalconnectorscostingabout$0.50persquarefoot(FEMA,2016b)

PublicStormShelters:APlanforNorman,Oklahoma

JoshHatzisDepartmentofGeographyandEnvironmentalSustainability,UniversityofOklahoma

Results• EveninahighrisklocationlikeOklahomathecostofa

stormshelterexceedsthevalueofastatisticallife($10million).• Shelterlocations(Figures3& 4)andtotalcost(Table2)

• ThecostperlifesavedforstormsheltersinNorman:• PermanentHome:$66.4million• MobileHome:$16.4million

Priority CostHigh $22,875,000.00Medium $43,671,000.00Low $136,387,200.00Total $202,933,200.00

Size Capacity CostPerPersonPersonal/Family upto16 $600.00Neighborhood 16to200+ $700.00Community 200- 1500+ $1,000.00

Figure3.Proposedshelterlocationsbypriority(top)andsize(bottom)

Figure4.ShelterplacementnearMadisonElementaryinNorman.Circlesrepresentcoverageareasforeachshelter.

Figure1.Annualtornadorisk(top);Tornadopathsbyintensity(bottom).

Figure2.LocationsofvulnerableareasinNorman(top);LocationofrefugeareasatUniversityofOklahoma(bottom).

Figure5.Costperlifesavedinmillionsofdollarsforpermanenthomes(top)andmobilehomes(bottom)

Table1.Sheltersizesandmarketcost. Table2.Totalcostforshelters

ReferencesCityofNorman.2016.NormanInteractiveMap.Availableat:<http://maps.normanok.gov>Cutter,S.L.,Boruff,B.J.,&Shirley,W.L.(2003).Socialvulnerabilitytoenvironmentalhazards.Socialsciencequarterly,84(2),242-261.FederalEmergencyManagementAgency(FEMA).2010.WindRetrofitGuideforResidentialBuildings.FEMAP-804.Availableat:<https://www.fema.gov/media-library-data/20130726-1753-25045-2304/508versioncombined_804.pdf>FederalEmergencyManagementAgency(FEMA).2016a.HazardMitigationPlanning.Availableat:<https://www.fema.gov/hazard-mitigation-planning.>FederalEmergencyManagementAgency(FEMA).2016b.WindBestPractices.Availableat:https://www.fema.gov/media-library-data/1428341633701-950983a86c2894a823c1cf9b843f6e14/Wind-BPs.pdfJohnston,DC.2013.05.22.MoreTornadoShelters?NotNecessarily.TheDailyBeast.Availableat:<http://www.thedailybeast.com/articles/MinnesotaPopulationCenter(MPC). 2016.NationalHistoricalGeographicInformationSystem:Version11.0[Database].Minneapolis:UniversityofMinnesota.http://doi.org/10.18128/D050.V11.0.Availableat:<https://www.nhgis.org>Simmons, K.M.,&Sutter,D.(2006).Directestimationofthecosteffectivenessoftornadoshelters.Riskanalysis,26(4),945-954.StormPredictionCenter(SPC).2016.SVRGIS:SevereWeatherDatabase.Availableat:<http://www.spc.noaa.gov/gis/svrgis/>