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Flashcards in Wildfires Deck (26):
1

The 3 types

Surface fires

Ground fires

Crown fires

2

Whats a Surface fire

the MOST COMMON

-They burn along the forest floor
= burn leaf litter and fallen branches

-Burn at 900*C

-Easy to control & cool quickly

3

Whats a Ground fire

-They burn organic matter in the soil as PEAT

-Smoulder at 540*C

4

Whats a Crown fire

-They burn through the top layer of foilage (CANOPY)

-1100*C temperature

-AFFECTS THE WHOLE FOREST

-Hard to control

5

Whats a WIldfire

An uncontrolled rural fire affecting different layers of vegetation = ladder effect
=explains the spread of forest floor fires top the Canopy/Foilage

Semi-natural hazards

6

What conditions to wildfires like?

Favourable to and like:

-A ready supply of fuel

DRY VEGETATION,
CLIMATIC WEATHER CONDITIONS

IGNITION SOURCES both human/natural intervention - someone throwing a cigarette

7

Wildfire behaviour

Speed and direction will be dependent on the TYPE OF VEGETATION (FUEL) and the CLIMATIC + TOPOGRAPHY characteristics

8

An area at risk of wildfires

AMERICA as a top target

-11cm rainfall all year
-Forest thins out to reduce its density/concentration
-Arsen crime / phone lines can trigger it

9

Vegetation types

influencing the spread and and intensity (heat energy output + degree of threat)

-MOISTURE CONTENT as a significant factor in these wildfires forming

-Eastern. Austrailia > where fire season migrates from the North in Spring to the South in Autumn - because of the rainfall seasons
^^^^^ a reason to why AUS suffers to many wildfires because of the nature of the fuel
^^^^^ EUCALYPTUS as fire-promotingwith the oils in the leaves exploding in intense fires

10

Wind direction + speed

-The most intense wildfires occur in DRY, WINDY CONDITIONS with LOW HUMIDITY in the early afternoon

-The wind WAFTS the flames and drives the flame forward
-wind velocity increases so the fire rate of movement increases

-Strong winds PREVENT A CONVECTION CURRENT FORMING

11

What happens if its BELOW 7% VELOCITY?

its a high risk

dry air and variable humidity during the day causes a risk

12

Topography

-They travel faster uphill
^^^^ the steeper the gradient, the faster they travel

-they travel IN THE DIRECTION OF AMBIENT WINDS that flow uphill

-The heat and smoke RISES means that fires can PRE-HEAT THE VEGETATION for easier combustion and burning

13

How the wildfires are caused?

Natural occurrences
^^^lightening, volcanic eruptions, rock fall sparks

Human intervention
^^^ 90% of US forest fires caused by humans

14

How they happen

Santa Ana winds and Southern California

- Clockwise flow of air from the Desert Winds around a HIGH PRESSURE SYSTEM east of the Sierra Nevada mountains

-Air from the mountains is compressed + warmed = less humid
-lower humidity dries out vegetation + wafts existing fires

-Winds squeeze through areas with fast gusts of winds (65-95km/h)

-The strong winds create turbulence & interstate human travel difficult

15

Wildfire Environmental IMPACTS

PRIMARY

-destroys habitats and ecosystems
-atmospheric pollution = smoke and water pollution as toxic ash gets in rivers
-carbon dioxide through trees being burnt (CARBON STORES)
-food chains/food webs impacted = death of animals

SECONDARY

-increased carbon emissions, ghg + climate change
-ecosystem developing again
-lack of nutrient stores without trees as more flooding and less soil nutrients

16

Wildfire Social IMPACTS

PRIMARY

-loss of life and injuries
-people forced to live elsewhere and be DISPLACED
-power line damage with winds
-mobile phone stations affected mean a lack of communication

SECONDARY

-need for a new way to inject income to the area with businesses destroyed so no income in the area
-new rules and regulations since the wildfire they need to abide by (no walking near this area)

17

Wildfire Economic IMPACTS

PRIMARY

-financial loss with the damage caused
-businesses destroyed
-crops and livestock lost
-services and homes destroyed (schools etc)

SECONDARY

- cost of rebuilding or relocating
-replacing livestock, crops, land, food lost
-cost to prepare better in the future + mitigate

18

Wildfire Political IMPACTS

PRIMARY

-emergency service action
-local/national government response with the state of emergency urgency or not
-local authorities and emergency services under pressure to prioritise after the immediate outbreak

SECONDARY

-strategies for preparedness and mitigation
-decisions into future regulation, compensation, replanting the forests
-over viewing laws again about use of the forest and countryside

19

How to manage wildfires

Preparedness
Mitigation
Prevention
Adaption

20

Wildfire management

PREPAREDNESS

Community preparedness = early detection
-rural firefighting teams in some countries

Warnings being released in times of high risk fires (social media)
^^USA National Weather Service issuing weather warnings alerting fire teams and residents

Red Flag Warning = weather conditons of extreme fire behaviour can be met in the next 24 hours - HIGHEST LEVEL OF WARNING
-RESIDENTS ARE URGED TO BE EXTREMELY CAUTIOUS
Fire Weather Watch = when these weather conditions can commence in the next 24-48 hours

Establishing firebreaks / a 'defensive space' around their home
*stacking firewood away from home
*trimming branches
*clean roof and gutters of leaf litter
*reduce density of any surrounding forest

21

Wildfire Management

MITIGATION

Reducing the severity of an event and supporting it after

EARLY FIRE DETECTION

-Satellites + infrared sensors can detect thermal variation
-Cameras are used to detect early ignition of fires, especially after lightening strikes

-NASA developing drone technology for surveying areas of vast landscape ~ has a range about 13km and can fly for an hour

22

Controlling / mitigating a wildfire

Removing the fuel/vegetation
Deliberately back burning vegetation
Using natural barriers ie. RIVERS to control fire spread

= SPOTTING where embers are carried far from the active fire can start a new fire being ignited elsewhere

Disaster aid + fire insurance ~ raising money for those affected

23

Wildfire Management

PREVENTION

Controlled burning reduces the fuel (dead leaf and litter matter) but can still get out of control

Impact ecosystems and nutrient cycles by reducing the litter stores + releasing carbon dioxide into the atmosphere

Public awareness in campsites and public areas
~ use of campfires and bonfires regulations being enforced

24

Why wildfires may be a positive thing?

Fires are a natural regenerative process within forest ecosystems

Should be allowed in certain circumstances to take their course

25

Wildfire Management

ADAPTATION

Involves learning to live with the threat of these wildfires and letting them take their course

Have a role to play in ECOSYSTEM DEVELOPMENT
^^^ burn away old and diseased wood material
~ enable fresh growth

Planning regulations to reduce the hazard associated with wildfires - restricting access to areas of risk during the fire season

Building design made up of products not causing pollution if they burn down

A risk taken by those who wish to live in a fire prone area

26

Alberta wildfire 2016

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