What three factors are necessary for wildfires (or any type of fire) to start and be sustained?

Wildfires

A

Wildfires are normally the product of human negligence . Humans start about 90% of wild fires and lightning causes the other 10%. Regular causes for wildfires include arson, camping ground fires,
throwing away cigarettes, burning rubbish, and playing with fireworks or matches. Once begun, wildfires tin can spread at a rate of upward to 23 kph and, as a burn down spreads over a mural, information technology could
undertake a life of its own – doing different things to go along itself going, fifty-fifty creating other blazes by throwing cinders miles away.
Three components are necessary to start a fire: oxygen, fuel and rut. These three brand upwardly "the fire triangle" and burn fighters often talk about this when they are attempting to put out
blazes. The theory is that if the burn down fighters can remove one of the triangle pillars, they can accept control of and eventually put out the fire.
B
The speed at which wildfires spread depends on the fuel effectually them. Fuel is any living or dead material that will burn. Types of fuel include anything from trees, underbrush and grassland
to houses. The quantity of inflammable material effectually a fire is known as "the fuel load" and is determined by the amount of available fuel per unit of measurement area, normally tons per acre. How dry the fuel
is can likewise influence how fires bear. When the fuel is very dry, it burns much more quickly and forms fires that are much harder to control. Bones fuel characteristics affecting a fire are size and shape, organization and moisture, but with wildfires, where fuel commonly consists of the same blazon of material, the main factor influencing
ignition fourth dimension is the ratio of the fuel'southward total surface area to its book. Considering the surface surface area of a twig is not much bigger than its book, it ignites rapidly. Notwithstanding, a tree'southward surface area is much
smaller than its book, so it requires more fourth dimension to heat upwards earlier ignition.
C
Iii weather variables that bear on wildfires are temperature, current of air and wet. Temperature straight influences the sparking of wildfires, as rut is one of the three pillars of the
fire triangle. Sticks, trees and underbrush on the ground receive oestrus from the dominicus, which heats and dries these potential fuels. College temperatures allow fuels to ignite and burn down more than apace
and add to the speed of a wildfire's spread. Consequently, wildfires tend to rage in the afternoon, during the hottest temperatures.
The biggest influence on a wildfire is probably wind and this is also the about unpredictable variable. Winds provide fires with extra oxygen, more dry out fuel, and current of air also makes wildfires
spread more quickly. Fires also create winds of their own that tin be upwards to 10 times faster than the ambient wind. Winds can even spread embers that can generate additional fires, an outcome
known as spotting. Winds also alter the grade of fires, and gusts can accept flames into trees, starting a "crown fire". Humidity and precipitation provide moisture that can slow fires down and reduce their intensity, as information technology is hard for fuel to ignite if information technology has high moisture levels. Higher levels of humidity mean fewer wildfires.
D

Topography can likewise hugely influence wildfire behaviour. In dissimilarity to fuel and weather, topography hardly changes over time and can help or hamper the spread of a wildfire. The
chief topographical factor relating to wildfires is gradient. As a rule, fires movement uphill much faster than downhill and the steeper the slope, the quicker fires motility. This is considering fires motion in the
aforementioned direction of the ambient wind, which by and large blows uphill. Moreover, the fire can preheat fuel further uphill as smoke and oestrus rise in that direction. On the other hand, when the burn
reaches the top of a hill, information technology has to struggle to come back downwards.
E
Each year thousands of fire fighters risk their lives in their jobs. Elite burn fighters come in two categories: Hotshots and Smokejumpers. Operating in 20 homo units, the primal task of hotshots
is to construct firebreaks around fires. A firebreak is a strip of land with all potential fuel removed. As their proper name suggests, smokejumpers jump out of aircraft to reach smaller fires situated in
inaccessible regions. They try to incorporate these smaller fires before they plough into bigger ones. As well as constructing firebreaks and putting water and fire retardant on fires, fire
fighters also use "backfires". Backfires are created by fire fighters and burn towards the main fire incinerating any potential fuel in its path.Fire fighters on the footing also receive extensive support from the air with tankers dropping thousands of gallons of h2o and retardant. Dropped from planes and helicopters, retardant is a
red chemical containing phosphate fertilizer, which slows and cools fires.

READING PASSAGE 1 Questions ane – 13
You should spend about 20 minutes on Questions i – 13 which are based on
Reading Passage 1 below.
Questions 1 – 4
Reading Passage 1 has 5 paragraphs (A – E).
From the list of headings beneath choose the most suitable headings for paragraphs
B – E.
Write the appropriate number (i – viii) in boxes i – 4 on your answer sail.
NB There are more headings than paragraphs, then you will not use them all.

Example Answer
Paragraph A 3

i Climate Conditions
two Solutions from the Air
three Fire Starters
iv Battling the Blaze
v The Lie of the Country
vi Rain – The Natural Saviour
vii Fuelling the Flames
viii Fires and Copse

Questions 5 – ix
Using NO MORE THAN THREE WORDS from Reading Passage 2, reply the
following questions.
Write your answers in boxes 5 – 9 on your answer sail.

5 Complete the last pillar of the fire triangle.

Δ

(5) _______________

heat fuel
source

Source: National Oceanic and Atmospheric Administration
6 What is measured in tons per acre?
seven When do wildfires burn at their fiercest?
eight What can travel in the current of air to create fires at some distance from the initial burn?
9 Proper noun a method using an additional fire that fire fighters utilise to control wild fires.

Questions 10 – 13
Complete each of the following statements (Questions ten – 13) with words taken from
Reading Passage 1.
Write NO More THAN Iii WORDS for each answer.
Write your answers in boxes x – 13 on your reply sheet.

10 The most important cistron in how quickly a wildfire catches fire is the surface
to volume _____________________.
xi The most significant weather factor to affect wildfires' actions is _____________________.
12 Fires on the tops of trees are known as _____________________.
13 Wildfires commonly travel much faster _____________________ because of the typical
direction of prevailing winds.

[shc_shortcode class="shc_mybox"]

1. vii
2. i
3. v
4. iv
5. Air/oxygen
6. The fuel load
7. In the afternoon
viii. Embers
9. Backfire(south)
ten. Ratio (of fuel)
11. The wind
12. Crown fires
xiii. Uphill[/shc_shortcode]

Wildfires ielts reading practice test

Wildfires ielts reading practice test

Wildfires ielts reading practise test

Wildfires ielts reading practice test

Wildfires ielts reading do test

Wildfires ielts reading practice examination

Wildfires ielts reading exercise examination

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Source: https://ieltsdata.org/wildfires-2/