1. What causes California wildfires?
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2. What causes fires to spread?
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3. Southern California Is Mountainous
Wpdms_shdrlfi020l_tehachapi_mountains.jpg (300 × 315 pixel, file size: 51 KB, MIME type: image/jpeg)Tehachapi Mountains ｩ 2004 Matthew Trump; Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
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4. Hot air rises, fanning flames on mountain slopes..
NASA's Ikhana unmanned research aircraft flew over several of the Southern California wildfires Wednesday, Oct. 24, with its sophisticated thermal-infrared imaging equipment peering through smoke and haze to record high-quality imagery of the hot spots. The above 3-D images were taken at 10:21 a.m. PDT over the Harris Fire in San Diego County, looking west. The hot spots (in yellow) are concentrated on the ridgeline in the left center of the photo. Downloaded from: on

5. Effect of Santa Ana Winds
NASA photo shows smoke plume over Pacific caused by powerful Santa Ana winds in So Cal
The winds fanned the fires and caused their rapid spread
The latest NASA photo of the Southern California wildfires, above, is nothing short of breathtaking ... and not in a good way.The red pixels represent fire activity.Worse yet, this photo was taken on Tuesday at 2:25 p.m. Eastern Time, well before fire officials began to speak of hope that changing weather conditions might bring some relief.According to the space agency: "NASA satellites have obtained new images of the California wildfires, illustrating the immense scale of the blazes. The National Interagency Fire Center reports that 12 large, uncontained fires have burned over 335,000 acres in Southern California. The fires have continued to spread due to the fierce, dry Santa Ana winds.” Downloaded from: on

6. What causes Santa Ana winds?
High pressure area over the Great Basin
Low pressure area over the Pacific
Air from the high flows to the low
The greater the difference between the high and the low, the stronger the winds
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7. Another Santa Ana Effect…
As the high-altitude winds from the Great Basin sweep down the mountain slopes and descend to sea level,
they warm up and dry out because of the increase in air pressure at that altitude.
That's what makes the Santa Ana winds so withering.
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9. Why Are Some Years More Dangerous than Other Years?
A wet spring causes lots of new brush to grow
If a dry autumn follows, that leaves lots of dried brush to burn
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10. Human Life Choices
Original people who lived in Los Angeles area, the Tongvas, called San Fernando Valley the “Valley of the Smokes.”
To live successfully near the mountains, Californians must learn to exercise awareness of the natural environment.
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