1. FIRE BEHAVIOR

2. Surface fire: Ground: Crown: Three types of fire behavior Fuels at or near the surface Subsurface organic fuels (duff, organic soils) Tree crowns

3. Categories of fires according to human management action: Wildfire: Management ignited prescribed fire: Prescribed natural fire: Suppression action is taken Ignited to meet a management objective Allowed to burn under a management plan to preserve natural role of fire

4. Fire Behavior: The Wildland Fire Environment WeatherTopography Fuels FIRE

5. Weather Components of the Wildland Fire Environment TemperatureTemperature Relative HumidityRelative Humidity Atmospheric StabilityAtmospheric Stability Windspeed and DirectionWindspeed and Direction PrecipitationPrecipitation

6. Topography Components of the Wildland Fire Environment ElevationElevation Position on SlopePosition on Slope AspectAspect Shape of CountryShape of Country Steepness of SlopeSteepness of Slope

7. Fuels Components of the Wildland Fire Environment Fuel LoadingFuel Loading Size and ShapeSize and Shape CompactnessCompactness Horizontal ContinuityHorizontal Continuity Vertical ContinuityVertical Continuity Chemical ContentChemical Content

8. Effects of topography on fire behavior.

9. Fuel load Temperature Winds Moisture

10. Effect of Aspect on Fuel Temperature and Moisture Wind Direction Fuels Transition Earlier Heating Earlier Cooling Generally Lee Side of Mountain Lightest Fuels Lowest Fuel Moisture Highest Temperature Earlier Curing of Fuels Earlier Snow Melt Fuels Transition Later Heating Later Cooling Generally Windward Side of Mountain Heaviest snows Highest Moisture Lowest Temperature Later Curing of Fuels Late Snow Melt

11. Slope Affects Fire Behavior Preheating Draft Faster Ignition and Spread Burning Material Rolling Downslope

13. Characteristics of Fire Behavior FIRE INTENSITY – Heat release per unit time (BTUs or KJ) Fire Intensity Affected by Fuel loading Fuel moisture content Compactness or arrangement of fuels

15. Flaming Zone Flame Length Flame Height Spread Direction

16. Rate of spread = distance/time Rate of Spread (ROS) The distance a fire travels during a given period of time. Burned Area Increased fire intensity Windspeed Steepness of slope Primary factors affecting rate of spread?

17. 4 acres 16 acres 36 acres (front)

18. Team Work Construct a sentence using your term(s) that explains the behavior of a particular fire situation but WITHOUT USING THE TERM IN THE IN THE EXPLANATION– the rest of the class should be able to determine what the term is based on your explanation.

19. Running Creeping Smoldering Spotting Spot fires Fire brand Torching Crowning Flareup Blowup Fire Whirls Wildfire Management ignited prescribed fire Prescribed natural fire Ground fire Surface fire Crown fire Chimney effect Slope reversal Chimney Effect Slope Reversal

20. Bottom of a Narrow Canyon Bottom of a Narrow Canyon

22. Slope Reversal Slope Reversal

23. Ground fire: Surface: Crown: Three types of fire behavior Subsurface organic fuels (duff, organic soils) Fuels at or near the surface Tree crowns

24. Categories of fires according to human management action: Wildfire: Management ignited prescribed fire: Prescribed natural fire: Suppression action is taken Ignited to meet a management objective Allowed to burn under a management plan to preserve natural role of fire

25. Running Types of fire behavior – spreading quickly Creeping – spreading slowly with low flames Smoldering– burns without flames; barely spreading Spotting– sparks/embers carried by wind or combustion column or moved by gravity Spot fires– new ignition points Fire brand– a piece of burning material

26. Torching Types of extreme fire behavior – surface fire moves into crowns of individual trees Crowning – spreads from tree crown to tree crown (dependent, active, or independent) Flareup – sudden acceleration of fire spread or intensity (short duration, for portion of fire) Blowup– dramatic change in the behavior of the whole fire (rapid transition to a severe fire) Fire Whirls– vortex (gas mass with rotational motion)

27. Fire Affects Its Own Environment Local Winds Atmospheric Stability Clouds/Precipitation Fuel Temperature Fuel Moisture

28. Wind-driven fire behavior Plume-dominated fire behavior (with downbursts)