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 Wildfires.
They are an ongoing threat in every U.S. state, in wooded and rural
areas. Yearly, they devour millions of acres of wilderness, and destoy
many homes and buildings. Wildfires are responsible for many injuries
and deaths among area residents and emergency workers. Four out of
every five wildfires are started by humans. These start mostly from
negligent behavior, such as not completely putting out camp fires,
or properly extinguishing cigarettes. The remaining 1 out of 5 are
usually set by lightning. They often begin unnoticed, but quickly
grow to become raging, out of control monsters, some moving through
an area at an average speed of 15 miles per hour. After reaching this
colossal size, they are nearly impossible to bring under control.
It takes many days to weeks, and many emergency workers and volunteers
working together to stop these fires from wiping out whole neighborhoods.
 A
fire needs three components to ignite and survive. These components
are a fuel source (something that will burn), heat, and oxygen. If
one of these is missing from the equation, the fire cannot occur or
does not survive. Dry wilderness is one of the most perfect fuel sources.
When combined with an oxygen filled breeze, all that is missing is
heat. Once heat is applied and the fuel source reaches its flash point
(point at which it will ignite). A wildfire can start with the blink
of an eye. Add in a bolt of lightning or a spark from a neglected
camp fire, and the equation is complete. As long as all, parts of
the equation remain in place, the wildfire will continue to burn.
Should one part be eliminated, the fire will decrease, and eventually
go out, unless that missing element is restored again. Weather, type
of fuel, and land topography are also factors that influence a fire's
life cycle and size.
 Dry,
hot, breezy weather is the most ideal for the groth of fires.Warmer
temperatures allow for fuels to ignite and burn faster, adding to
the rate at which a wildfire spreads. For this reason, wildfires tend
to rage in the afternoon, when temperatures are at their hottest.
Wind probably has the biggest impact on a wildfire's behavior. It
is also the most unpredictable factor. Winds supply the fire with
additional oxygen, further dry potential fuel and push the fire across
the land at a faster rate. Larger fires have even been known to create
their own wind and weather patterns. They start to feed upon themselves
and may even create large vortices called fire whirls. They resemble
tornadoes, and have been know to throw burning debris considerable
distances. This behavior commonly spreads a wildfire much faster,
pushing it into yet untouched areas.
 Fuel
can include everything from trees, underbrush and dry grassy fields
to homes. The amount of flammable material that surrounds a fire is
referred to as the fuel load. A small fuel load will cause a fire
to burn and spread slowly, with a low intensity. If there is a lot
of fuel, the fire will burn more intensely, causing it to spread faster.
The faster it heats up the material around it, the faster those materials
can ignite. The dryness of the fuel can also affect the behavior of
the fire. When the fuel is very dry, it is consumed much faster and
creates a fire that is much more difficult to contain.
Slope or topography of land also plays a role in the spread of a fire.
"Unlike humans, fires usually travel uphill much faster than
downhill. The steeper the slope, the faster the fire travels. Fires
travel in the direction of the ambient wind, which usually flows uphill.
Additionally, the fire is able to preheat the fuel further up the
hill because the smoke and heat are rising in that direction. Conversely,
once the fire has reached the top of a hill, it must struggle to come
back down because it is not able to preheat the downhill fuel as well
as the uphill."
 In
addition to the damage that fires cause as they burn, they can also
leave behind disastrous problems, the effects of which might not be
felt for months after the fire burns out. When fires destroy all the
vegetation on a hill or mountain, it can also weaken the organic material
in the soil and prevent water from penetrating the soil. One problem
that results from this is extremely dangerous erosion that can lead
to debris flows.
When
there is a threat of a wildfire in your area, it is wise to heed all
warnings. Have a plan of action ready. please click on the link blow
for Wildfire Safty Tips.
(All
information obtained from the National
Interagency Fire Center, How
Stuff Works, and American
Red Cross)
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