QuestionsandAnswers
Q Whatwaslearnedfromthisstudyaboutwild iresontheFrontRange?
Fourmile Canyon
Fire Findings
July 2012
A Wild iresareacommonoccurrenceontheFrontRangeMountainsof
Colorado.Theaverage irereturnintervalinlowelevationponderosapine
(Pinusponderosa)forestsinthenorthernColoradoFrontRangevariesfrom8
to18years.Basedonresearchoverthepast40years,awild ireburns
structuressomewhereintheColoradoFrontRangeonanaverageofevery
twoyears.
Q Isthereanythinginthe inal indingsthatwasn’taddressedinthe
preliminary indings?
A The indingsdidnotchangebutwehaveaddressedcommentsonthe
preliminary indingsfromlandmanagersfromtheU.S.ForestService,Rocky
MountainRegion,ColoradoStateForestServiceandtheBureauofLand
Management.Aresponsetoallcommentsandasummarizedlistofindividuals
contactedbytheAssessmentTeamduringthecourseofthescienti icstudy
areprovidedinappendicesinthe inal indings.
Providing scientific
knowledge and
technology to sustain
our nation’s forests,
rangelands, and
grasslands
Q Howdidtheoverallconditionsaffect iresuppressioneffortsonthe
FourmileCanyonFireduringthe irst24hours?
A TheFourmileCanyonFirewasreportedat10a.m.onSept.6,2010and
spreadrapidlyinmultipledirectionsduetohighwindsandverylow
humidity.Thewindscarried irebrandsoveradistanceuptoahalfmileahead
ofthe lamefront,creatingnewspot ires.
Undertheseconditions,suppressioneffortsfocusedon ire ighterandpublic
safety,evacuations,andprotectionofhomeswhenandwheresafelyfeasible.
Highwindspeedsexceededsafe lyingconditionsandmaderetardantuse
ineffectivesoallaircraftweregroundeduntil5p.m.Helicopterscouldnotbe
useduntilthefollowingday.
For additional information,
contact:
G. Sam Foster
RMRS Director
970-498-1353
gfoster@fs.fed.us
Q Whatotherfactorscontributedtotheoverall irebehaviorofthis ire?
A Surfacefuelssuchasgrasses,shrubs,pineneedlesandsmallbrancheswere
contributingfactorsinthe irebehavioroftheFourmileCanyonFire.
Observersnotedrapid irespreadthroughsurfacefuelsintheopen
ponderosapineforestwithmanytreestorchingandspot iresstartingin
advanceofthe irefront.
D
A
F
B
USDA is an equal opportunity
provider and employer
C
E
E
D
Themosteffectivestrategyforreducingcrown ireoccurrenceandburnseverityisto1)reducesurfacefuelsD,E,F;2)remove
ladderfuelsB,C;increasecanopybaseheightsA;andlastlyreducecanopycontinuityanddensityA.PhotosRussGraham
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QuestionsandAnswers
Fourmile Canyon
Fire Findings
July 2012
Q Althoughfueltreatmentshadpreviouslybeenappliedtoseveralareas
withinthe ireperimeter,thestudyconcludedthesetreatmentshad
minimalimpactinaffectinghowthe ireburnedorthedamageitcaused.
Why?
A Fueltreatmentswereoftenfocusedonimprovingthehealthoftheforest,
developingsafetravelcorridors,andtocreatewild iredefendablezonesusing
ashadedfuelbreaknearhomesandcommunities.Surfacedebrisfromthe
treatmentshadnotbeenremovedeitherphysicallyorbyprescribed ire.
Thus,theef icacyofthefueltreatmentswasverylimited.
Whatwelearnedfromthisstudyisconsistentwiththeknowledgethat
surfacefuelremovalplaysanimportantroleinchanging irebehavior.
Providing scientific
knowledge and
technology to sustain
our nation’s forests,
rangelands, and
grasslands
For additional information,
contact:
G. Sam Foster
RMRS Director
970-498-1353
gfoster@fs.fed.us
Highwindspeedsandlowairhumidityarecommonweatherconditions
associatedwithlargewild iresalongtheFrontRange.Recognizingthesehigh
windspeedsandlowrelativehumidityconditionsiscriticalwhendeveloping
fueltreatmentprescriptions.Weneedtoappropriatelydesignfueltreatments
—treatingsurfacefuels,ladderfuels,andcanopyfuelsinthisorderof
importance—inandamonglandscapesinconjunctionwithtreatingfuelsin
thehomeignitionzones(HIZ)acrosstheFrontRangetoimprovethe
effectivenessoffueltreatments.
Q Whatisthebestdefenseforhomesurvivability?
A CreatingandregularlymaintaininganHIZisahomeowner’s irstandbestline
ofdefense.Survivalordestructionofhomesexposedtowild ire lamesand
irebrandsisnotdeterminedby
theoverall irebehavioror
distanceof irebrandloftingbut
rather,theconditionoftheHIZ—
thedesign,materialand
maintenanceofthehomein
relationtoitsimmediate
surroundingswithin100feet.For
moreinformationregardingHIZs
gotohttp://csfs.colostate.edu/
pages/wf‐protection.htmlor
www. irewise.org.
FourmileCanyonFirephoto©JoeAmon,AP
ExampleofanHIZandhowitreducesignitionpotentialwithin
100feetofahomeunderextremeconditions.
USDA is an equal opportunity
provider and employer
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