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Exploring the beautiful nature of California
California Nature: Earth Wind & Fire
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California's climate is often compared to
that of the Mediterranean, due to warm, dry summers, and mild,
wet winters. On the coast, average yearly temperatures range
between the low 40s°F and in the high 70s°F and 80s°F.
Farther inland, summers are hot and dry, and at higher altitudes
the weather is more typical of a four-seasons cycle with cold,
snowy winters. The contrast is clear in the state’s two largest
cities, where you’ll find very different weather patterns. San
Francisco is famous for its fog, especially in the summer, and
Los Angeles is known for its consistently sunny, desert-like,
coastal climate.
Locals jokingly refer to the “four seasons” of California as
fire, mudslides, earthquakes, and drought. 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.
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Many people living throughout much of the continental United
States may not be too concerned about a wall of mud, water, and
debris swallowing up their homes and potentially endangering
their lives, but those living near wildfire burn areas in
regions such as Southern California may tell another story.
In the United States, approximately 25 to 50 deaths a year can
be attributed to the phenomenon of debris flow, or mudslides as
they are more commonly known, with monetary losses exceeding $2
billion annually.
These gravity-driven mixtures of sediment, water, and other
dislodged objects are caused by heavy rainfall or rapid
snowmelt, and weakened terrain, creating a deadly slurry of
dislodged rocks, soil, and trees. These ingredients combine to
resemble a wet concrete-like mass that can develop tremendous
downhill force and leave a path of destruction in its wake.
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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.
Named after Southern California's Santa Ana
Canyon and a fixture of local legend and literature, the Santa
Ana is a blustery, dry and warm (often hot) wind that blows out
of the desert. Local legends associate the hot, dry winds with
homicides and earthquakes, but these are myths.
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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. The wind also picks up dust, and during Santa Ana wind events,
dust plumes carried by strong offshore winds can be seen over
the ocean from space.
When a high pressure system develops over the Great Basin to the
north and east of Southern California, prevailing winds push the
air in a clockwise direction around the high pressure. Santa Ana
winds are caused by this phenomenon, especially when lower
pressure to the west actually pulls the air across Southern
California in strong offshore winds. |
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An
earthquake is a trembling or shaking of the ground caused by the
sudden release of energy stored in the rocks below the surface,
radiating from a fault along which movement has just taken
place. Earthquakes can occur at any time of the year and at any
time of the day or night. Earthquakes occur under all weather
conditions, sunny, wet, hot, or cold--without special tendency.
The largest recorded earthquake in California was the 1857 Fort
Tejon earthquake, with an estimated magnitude of 8.0. This
earthquake ruptured the San Andreas Fault from Parkfield to
Wrightwood, a distance of 225 miles
The most destructive earthquake to date was the 7.9 magnitude
1906 San Francisco earthquake, in which over 3000 people
perished in the earthquake and the fires that followed. The 1906
quake ruptured the northern segment of the San Andreas Fault for
296 miles, from San Juan Bautista to near Cape Mendocino in the
north.
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