How Do the Santa Ana Winds Work?

The Santa Anas are winds that sweep hot air over Southern California, both clearing the air and exacerbating wildfires. Learn how they work in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/nature/climate-weather/atmospheric/santa-ana-winds.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeart Radio. Hey
brain Stuff, Lauren Vogelbaum. Here, when the Santa Ana winds
blow in southern California, everyone takes notice, too many in
the region, writers, singers, poets, and everyone else. They're a harbinger,
mostly of no good. Scientifically speaking, the Santa Anna's are

(00:26):
something else, entirely a perennial natural phenomenon whose future effects
are now warped by a warming planet. Climate scientist Alexander
Gershnov with the scripts Institution of Oceanography at UC San
Diego told the university's news service in early nineteen climate
change has been projected to lengthen the dry season in

(00:48):
California and other Mediterranean climate regions, making vegetation more likely
to remain dry into December. These changes, together with the
projected lessening of least season Santa Ana winds, suggest that
southern California's wildfire season could shift toward winter, longer, more

(01:09):
dangerous dry seasons, wildfires raging later in the year, changes
in the winds. It's potentially dramatic stuff. It might seem
the stuff of Hollywood, but let's back up a step.
Santa Ana winds are dry and warm winds from the
Great Basin, an area that incorporates large parts of the

(01:30):
states of Nevada and Utah. The winds start in the
basins inland deserts east and north of southern California, and
then flow downward, taking a turn toward the Pacific Ocean.
The Santa Anna's are usually, but not always, late year
winds that form when the weather is cooler in the
Great Basin. They don't begin in hot deserts. They actually

(01:53):
start off as cool winds and are pushed towards southern
California by high pressure systems. But as the wind's head
down slope, they get both warmer because air generally heats
up as it descends, and drier air only a mile
above your head right now maybe some thirty degrees fahrenheit
warmer than the air around you. In metric that's the difference,

(02:16):
say between twenty one degrees celsius where you are and
thirty eight some six up. It doesn't take much of
an altitude change to make a difference. Because of this
and a number of other circumstances, the Santa Annas have
a reputation. These winds most often whip into southern California

(02:36):
during the driest part of the year, providing a metaphoric
bit of gasoline to the already fire ready tinder in
the area. For example, in December of the Santa Anna's
fueled the largest fire in southern California's history, the Thomas Fire,
which burned four hundred and forty square miles that's eleven

(02:57):
thousand square kilometers Inventor and Santa Barbara Counties. The winds
also fanned the flames of the October two thousand seven
and two thousand three wildfires, and all of these have
caused serious damage to property and the people in wild
life that lived there from the fires themselves, but also
from smoke. According to a paper published in the journal

(03:21):
Geophysical Research Letters in the frequency of Santa ana wind
events is actually decreasing and may drop by an average
of eighteen percent by the end of the twenty first century.
This is largely because the Great Basin will have fewer
days of the cold weather that's necessary to form the winds.
Though that may sound like good news, it's not. The

(03:44):
Santa Anna's will still have a busy period as they
do now, and it will come in the peak of
a later possibly longer wildfire season. That peak will shift
from October into November and the early winter months, which
could lead to bigger wildfires that burn longer. As a

(04:05):
weather phenomenon that's unique to southern California, the Santa Anna's
have long been associated with a certain feel. Novelist Raymond Chandler,
a long time so Cal resident famed for detective stories
like The Big Sleep, described a windy Santa Anna knight
in his short story Red Wind. Quote. On nights like that,

(04:27):
every booze party ends in a fight. Meek little wives
feel the edge of the carving knife and study their
husband's necks. Anything can happen. You can even get a
full glass of beer at a cocktail lounge. On the
other hand, Santa Anna's can sweep out impurities in the air,
provide welcome warmth, and offer bright blue skies and stunning

(04:48):
sunsets in the winter. The Beach Boys took this more
upbeat look at the winds and their song Santa Ana Winds,
fill my sails a desert wind and hold the waves
high for me. Then I will come and test my
skill where the Santa Ana winds blow free. Still, too
many residents in the area the Santa Annas have an

(05:11):
ominous feel to them. Essayist Joan Didion wrote in her
essay The Santa Anna's, published as part of Los Angeles
Notebook and Slouching towards Bethlehem in I have neither heard
nor read that a Santa Anna is due, but I
know it, and almost everyone I've seen today knows it too.
We know it because we feel it. The baby frets,

(05:32):
the maide sulks, I rekindle a waning argument with the
telephone company, then cut my losses and lie down, given
over to whatever it is in the air. To live
with the Santa Anna is to accept, consciously or unconsciously,
a deeply mechanistic view of human behavior. Whatever lies in

(05:53):
store for the Santa Annas and all they reap is
still a matter for the future. But for now, the warm,
dry i winds continue to blow the citizens of southern California.
You can feel it. Today's episode is based on the
article what are the sent to Anna Winds? On House

(06:13):
to forwarks dot com, written by John Donovan. Brainstuff is
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