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Exploring the beautiful nature of California
California Nature: California Wildfires
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Fire season is year-round in Southern
California, but it peaks from April or May to October or
November, and sometimes through January. Every fire season is
different. There are a lot of different factors that play a part
in why a fire season might be quiet or severe. Rainfall and snow
can help keep plants from dying, while keeping the soil moist.
Onshore flows can keep the Inland area cooler and more humid
through early August and may prevent monsoonal storms from
building over California deserts, eliminating many lightning
storms that spark fires. One of the biggest factors in Southern
California wildfires is the Santa Ana Winds.
Named after Southern California's Santa Ana Canyon, the Santa
Ana is a blustery, dry and often hot wind that blows out of the
desert. Local legends associate the hot, dry winds with
homicides and earthquakes, but these are myths.
Santa Ana winds are a fact of life in Southern California in the fall and
winter. Bringing hot temperatures, low humidity and strong winds at the end of
the dry season, the Santa Ana winds increase wildfire danger and have inspired
cultural references from literature to music. |
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While the Santa Ana winds may occur anytime between September and March, the
ones in October are most infamous, as this is also the peak of fire season. Many
of Southern California’s most devastating wildfires have been exacerbated by
Santa Ana winds, especially during times of drought when the coastal scrubland
or chaparral is brittle dry. These furious and sometimes deadly force winds move
from the East to the West across the state of California.
Beginning with a pocket of high pressure air, the wind moves
through the states of Nevada, Utah and Arizona pushing the air
up, up and up and then over The San Gabriel Mountains. This air
then accelerates down the west side of The San Gabriel
Mountains, gaining tremendous speed as it goes through the
canyons often reaching tropical storm force winds.
Although the Santa Ana winds originate as colder air over the
high desert, they arrive in Southern California as hot air
because of the difference in elevation. Air temperature is
strongly correlated to elevation, and if there was not a
dramatic difference in elevation between the Great Basin and the
Los Angeles Basin, the Santa Ana winds would reach Southern
California as cool winds. When air drops in elevation, however,
it becomes compressed and warmer. This is called adiabatic
warming. |
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Santa Ana winds are usually dry winds, which
further exacerbates the potential danger of wildfires. As the
air descends and warms due to compression, its relative humidity
decreases. Relative humidity can drop below 10% during a Santa
Ana wind event. Because of the low relative humidity, this hot,
fast-moving air can literally strip already dry vegetation of
whatever little moisture it may have, further increasing fire
danger.
Southern California forecasters typically issue a red flag
warning in advance of a Santa Ana Wind event. The red flag
warning generally covers the mountains of Los Angeles and
Ventura counties, the Santa Monica Mountains, and the San
Fernando and San Gabriel valleys. According to the National
Weather Service, a red flag warning means that “critical fire
weather conditions are either occurring now or will shortly.” |
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Sporadic fires are normal throughout California in the summer
and fall as temperatures rise and rainfall drops, causing
vegetation to die off and provide fuel for combustion. In
Southern California, the normal wildfire season begins in
October with the arrival of the infamous Santa Ana winds, and it
is unusual to see fires spread rapidly at other times of year.
During the height of California wildfires public health
officials recommend that outdoor activities should be limited
and people with respiratory conditions remain inside.
Wildfire impacts to wildlife range from positive to negative
based on a number of wildfire and environmental characteristics.
In California, many biological communities are adapted to fire.
These include conifer forests, oak woodlands, chaparral
shrublands and native grasslands. Fire is part of the ecosystems
that animals inhabit and animals respond accordingly.
Although fire is a very necessary element to healthy wildlife
habitats, fire can be devastating to individual animals. Most
animals will get out of harms way, but some might not be so
fortunate.
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It is when fires occur too frequently or
burn rapidly that wildlife are most impacted. Rapidly burning
fires give wildlife less time to react in fleeing or taking
shelter. The smoke, heat and flames of fast-moving fire fronts
are more likely to kill wildlife than slower-moving fire. If
orphaned or injured wildlife is found the best thing to do is
let “mother nature” take its course. If intervention is
absolutely necessary the public should notify a licensed
wildlife rehabilitation facility or DFG directly.
After a fire, wildlife may be temporarily displaced from previous habitats. This
displacement may be short-lived, just until surviving plants regrow and seeds
sprout. But displacement may take longer, requiring some years before the right
habitat exists for a particular animal species. Which animals are able to take
advantage of the new habitat depends on the severity, complexity and extent of
the wildfire. Although some animals may leave a burned area, many others will utilize the
newly burned area extensively. |
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