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LarryNanceWildfire

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LarryNanceWildfire

  1. 1. QUIZ – 3 principal environmental factorsthat affect wildland fire behavior?
  2. 2. ENVIRONMENTAL FACTORS AFFECTING WILDFIRES FUEL WEATHER TOPOGRAPHY
  3. 3. Fire Statistics
  4. 4. Fires by Month 1932 - 2011700600500400 Fires300200100 0 Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
  5. 5. Tom Foti /Susan Glenn
  6. 6. Oct- Dec Number of Fires by Year Fires8000 Feb-Apr Spr- Sum7000600050004000300020001000 0
  7. 7. June- August 2012 • 2,033 fires • 51,747 acresOther comparisons:Jan- March 1942•3,586 fires/118,610 ac.July-Sept. 1980•2,768 fires/73,070 ac.
  8. 8. Fires Larger Than 100 Acres #Acres County Date 537 Miller June 23 142 Franklin June 29 160 #Acres Clark County June 29 Date 400 104 Clark Lafayette June 29 July 19 110 109 Conway Faulkner June330 July 115 110 Hot Spring Conway July 1 June 30 250 115 Clark Hot Spring July 1 1 July 115 293 Dallas Logan July 4 1 July 116 Independence July 28 109 Faulkner July 3 140 White July 3 140 White July 3 142 Franklin June 29 471 160 Pope Clark July 3 June 29 115 179 Dallas Ashley August 4 July 3 116 199 Clark Independence July4 July 22 200 200 Dallas Dallas July 4 4 July 200 250 Benton Carroll August 4 July 7 232 Sharp August 15 104 Lafayette July 19 250 Clark July 1 199 Independence July 22 250 Carroll July 4 1,014 274 Yell Hot Spring July 25 July 30 116 o293 Independence Logan July128 July 355 300 Garland Van Buren August 29 July 28 355 274 Garland Hot Spring July 29 July 30 400 380 Clark Benton June 292 Aug. 471 Pope July 3 179 Ashley Aug. 3 537 Miller June 23 825 825 PerryPerry Aug. 13 August 13 852 852 Clark Clark Aug. 13 August 13 1,410 1,014 Drew Yell Aug. 14 July 25 232 1,410 SharpDrew Aug. 15 August 14 300 Van Buren Aug. 28
  9. 9. Fires by Cause (AVG) 1992 - 2011800700600500400 Fires300200100 0 Inc Debris Smokers Railroad Campfire Equip Children Lightning Misc
  10. 10. Extreme Fire Behavior Conditions
  11. 11. Extreme Fire Behavior Conditions:•Relative humidity is below 20%•Wind speeds above 20 mph•Dispersion Index value of 80+•Haines Index - 6•KBDI - 700-800•Fine fuel moisture below 5%•Dust devils/fire whirls•Spotting in several directions•Thunderstorm on the horizon
  12. 12. Relative humidity ≤ 20%
  13. 13. Wind Information 20 foot winds- ≥20 mph Winds at 20 feet above theground or 20 feet above theaverage height of vegetation are used in the routine fire weather forecast.
  14. 14. Dispersion Index ADI Description Poor dispersion, stagnant air if conditions 0-20 persist. Poor to fair dispersion, stagnation possible21-40 with low wind speeds.41-60 Generally good dispersion. Very good dispersion, control problems61-80 likely. Excellent dispersion, control problems 80 + expected.
  15. 15. Keetch-Byram Drought Index 0-200 Soil moisture and large class fuel moistures are high and do not contribute much to fire intensity. Typical of spring dormant season following winter precipitation.200-400 Typical of late spring, early growing season. Lower litter and duff layers are drying and beginning to contribute to fire intensity.400-600 Typical of late summer, early fall. Lower litter and duff layers actively contribute to fire intensity and will burn actively.600-800 Often associated with more severe drought with increased wildfire occurrence. Intense, deep burning fires with significant downwind spotting can be expected. Live fuels can also be expected to burn actively at these levels.
  16. 16. ThunderstormWindsStrong and shifting winds. Speeds often greaterthan 30 mph result in erratic fire behavior.Wind speeds often enhanced by the forwardmovement of the storm.Outflow typically precedes rain by 3-5 miles, butcan be much more.
  17. 17. Red Flag WarningCriteria• Afternoon minimum relative humidity expected to be 25% or lower.• 20 foot sustained winds in excess of 14 mph.• Fuels that are determined to be critically dry (less than 10 percent for 10 hour fuels).• Other parameters that are considered include the likelihood of lightning occurrence, wind shifts, and/or current wildfire activity.
  18. 18. On site WeatherObservations… Kestrel Belt Weather Kit

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