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Genesee Fire Rescue. Community Wildf ire Meeting. Denver Fire at Black Forest Fire. Heat Transfer. Convection. Conduction. Radiation. Three environmental factors of wildfire behavior that affect the spread of wildland fire. Weather. Temperature Wind Increases supply of oxygen.
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Genesee Fire Rescue Community Wildfire Meeting
Heat Transfer Convection Conduction Radiation
Three environmental factors of wildfire behavior that affect the spread of wildland fire.
Weather • Temperature • Wind • Increases supply of oxygen. • Drives convective heat into adjacent fuels. • Influences direction of spread and spotting. • Carries away moist air replacing it with drier air. • Dries fuels. • Raises fuel moisture if the air contains moisture. • Relative Humidity • As RH increases, fuel moisture increases. • Precipitation • Increases fuel moisture
Indicators of Problem and Extreme Fire Behavior • Strong Wind. • Sudden changes in wind direction and velocity due to weather fronts. • High, fast-moving clouds may indicate unusual surface winds. • Unexpected calm may indicate wind shift. • Thunderstorms above or close to the fire. • Unusually high temperatures and low relative humidity. • Dust devils and whirlwinds developing. • Bent smoke column. Weather Indicators
Aspect Topography NORTH Heavy fuels Shade Moist SOUTH Light fuels Sunny Dry
Flame is closer to and preheating fuel Steep Slopes CauseRapid Fire Spread Convection and Radiant Heat
Indicators of Problem and Extreme Fire Behavior • Steep slopes. • Chutes, saddles, and box canyons which provide conditions for “chimney effect.” • Narrow canyons may increase fire spread by radiant heat and spotting. Topography Indicators
Fuels Fuel Characteristics • Fuel Moisture • Size and Shape • Fuel Loading • Horizontal Continuity • Vertical Arrangement
Fuel Moisture The amount of water in a fuel expressed as a percentage of the oven-dry weight of that fuel. • CATEGORIES • 1-hour fuels: 0 – ¼ inch in diameter • 10-hour fuels: ¼ – 1 inch in diameter • 100-hour fuels: 1 – 3 inches in diameter • 1000-hour fuels: 3 – 8 inches in diameter
Categories of Fuel • Light Fuels: • Leaves • Grass • Shrubs • Heavy Fuels: • Limbs • Logs • Stumps
Fuel Loading The quantity of fuels in an area
Horizontal Continuity &Vertical Arrangement • Horizontal Continuity: • Uniform • Patchy • Vertical Arrangement: • Ground • Surface • Aerial
Uniform Fuels Patchy Fuels
Vertical Arrangement of Fuels Aerial Fuels Ladder Fuels Surface Fuels Ground Fuels
Indicators of Problem and Extreme Fire Behavior • Unusually dry fuels. • Large amount of light fuel (shrubs, grass, needles). • Fuels exposed to direct sunlight. • Fuels dried by prolonged drought. • Ladder fuels that allow a surface fire to move into the crowns of shrubs or trees. • Crown foliage dried by surface fire. • Concentration of snags. Fuel Indicators
Creeping Fire burning with a low flame and spreading slowly.
Running Fire spread rapidly with a well defined head. *Click on image to play video
Spotting Fire producing sparks or embers that are carried by the wind or convection that start new fires *Click on image to play video
Flare up Sudden acceleration of fire spread or intensity, but of relatively short duration.
Fire Whirl A spinning, moving column of ascending air rising within a vortex and carrying aloft smoke, debris, and flames.
Crowning Fire advances from top-to-top of trees or shrubs more or less independently of the surface fire. *Click on image to play video
Indicators of Problem and Extreme Fire Behavior • Keep an eye on the smoke column. Indicates direction of fire spread, location of spot fires, and changes in fire intensity. • Many simultaneous fires starting or smoldering fires beginning to pick up in intensity. • Fire begins to torch small groups of trees or shrubs. • Frequent spot fires occurring. • Fire-whirls beginning to develop inside the main fire. • Crown fires. Fire Behavior Indicators
Tactical Modes Offensive Defensive Combination 03-31-S215-EP
Offensive Mode Attack and contain the fire 03-32-S215-EP
Defensive Mode Set up at the house Clear flammable material Protect house from flame and sparks 03-33-S215-EP
Defensive Mode If too much fire or no defensible space, LEAVE! Return after fire front passes 03-34-S215-EP
Combination Offensive and Defensive Mode Structure engines at home for protection Attack fire and and drive flames away from house
Structure Triage “Size-Up” # 2 # 3 # 4 # 1 04-36-S215-EP
5 Top Effective Mitigation Measures Case Study of Witch and Guejito Fires • Well-irrigated area encircling structure for at least 30 feet on all sides. Plantings limited to carefully spaced low flammability species. • Provide added protection with “Fuel Breaks” like driveways, gravel walkways and lawns.
Keep vegetation pruned and limb trees 6–10 feet from ground. Remove leaf /needle clutter and dead and overhanging branches. • Periodically inspect your property, clearing dead wood and dense vegetation at a distance of at least 30 feet from your house. • Is the structure free of an attached wood fence? Footnote: Of the 241 homes impacted, 13 had wood shake roofs and all 13 were destroyed. A total of 89 were destroyed or damaged.
Things YOU can do to help us • Shut off natural gas and propane. • Place metal (not wooden) ladders against the lee side of your house. • Connect and turn off outside water hoses and nozzles. • If time permits, remove combustibles (patio furniture, firewood, etc.) within 30 feet of your home. • Close windows and doors to the house to prevent sparks and embers from blowing inside. Cover gable vents if time permits. • Close all doors inside the house to prevent draft. • Turn OFF fans, air conditioner, furnace.
Move furniture from windows. • Take down your drapes and curtains and close all blinds to deflect heat. • Fill all bathtubs, sinks and other containers with water to deflect heat. • Leave exterior lights on so responders can find your home at night. • Put on natural fiber clothing and take your 72-Hour kit with you. • Leave front door unlocked. • Put a white flag (towel, pillow case, etc.) outside where it can be seen from the roadway. Only Do The Above IF YOU HAVE TIME Evacuate Now Means NOW
Black Forest Fire 2013 – Video courtesy of Colorado Springs Fire Department
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