WILDFIRESWeek 9

QUESTIONS FOR DISCUSSION

Would you live in an area prone to wildfires? If so, where?

What level of risk from wildfires is acceptable to you? (How would you know if the subsidence risk was assessed accurately?)

What should be done by people and communities in areas prone to wildfires to prepare for the hazard and prevent catastrophe?

OTHER QUESTIONS TO CONSIDER What factors influence the impact

of wildfires? How do wildfire hazards vary from

place to place? Why?

The five concepts from Chapter 1

WILDFIRES

What is it? Self-sustaining Rapid High temperature “Biochemical oxidation reaction”

Releases Heat Light Other products

WILDFIRE REQUIREMENTS

WILDFIRE PHASES

Preignition – preheating & pyrolosis Temperature increases Water content decreases

Combustion Ignition Flaming Glowering/smoldering

Extinction

PARTS OF A WILDFIRE

FIRE ENVIRONMENT - FUEL

Sufficient quantity required to maintain fire and allow movement

Size Arrangement Moisture content

FIRE ENVIRONMENT – TOPOGRAPHY & WEATHER South-facing slopes Exposure to prevailing winds Steep slopes Dry conditions

Rain Humidity

Wind

TYPES OF FIRES

Ground Surface Crown

AREAS AT RISK

Any place with sufficient fuel Commonly

Dry grasslands Forests

Triggers Drought Disease Fire suppression

IMPACT OF WILDFIRES Water-repellent soils Mass wasting Soil erosion Vegetation Habitat

HUMAN IMPACT

Aesthetic Homes

RESPONSE TO WILDFIRES

Understand fire regime Remote sensing Prescribed burns Building codes Fire insurance Minimizing wildland/urban

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