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Death Valley
Fri Jul 09, 2004
Listen in RealAudio 
The hottest temperature ever recorded in the U.S.: 134 degrees Fahrenheit, Furnace
Creek, California, July 10, 1913. Hi, I’m Bryan Yeaton for The Weather Notebook.
Furnace Creek lies within California’s Death Valley. In one 43-day stretch in 1917, daily
maximum temperatures soared to 120F or more. In 1974, 134 consecutive days
reached or exceeded 100F.
So why is Death Valley so hot? As real estate agents would say: location, location,
location.
First, Death Valley sits on the edge of a global desert belt where persistent descending
air warms, and suppresses cloud and rain formation.
Next, the valley lies east of the Sierra Nevada Mountains, in the rain shadow. As a
result, average precipitation is only an inch and a half. The sun scorches the soil dry,
and in the summer, just bakes the ground day in and day out. Ground temperatures
may exceed 200 degrees, hot enough to fry an egg—easily.
Not only does Death Valley receive very little water, but when moisture originally held
within a passing air mass drops out over the mountain ranges, the water vapour
changes to liquid water that then rains out. This process produces heat—latent heat.
Like you needed more?
Now we have very warm, dry air, descending into Death Valley. In doing so, it further
heats by compression as it drops from high elevations, much like Chinooks or Santa
Ana winds.
Finally, Death Valley holds another surprise. Its elevation is 194 feet below sea level;
so further compressional heating adds an extra degree to the temperature.
For seven years, Furnace Creek held the world heat record, until that was nipped by
Azizia, Libya in 1922 with 136 degrees.
Thanks to our contributing writer, meteorologist Keith Heidorn. Our show is supported
by Subaru of America and the National Science Foundation.
Today's Links
Death Valley National Park:
http://www.death.valley.national-park.com/
Death Valley National Park - Hiking in the Heat:
http://gorp.away.com/gorp/resource/us_national_park/ca/hik2_dv.htm
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