1. California Wildfires

2. What causes fires to spread?

3. So. California Is Mountainous

4. Hot air rises, fanning flames on mountain slopes..

5. High Winds Blow East to West

6. 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  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

7. In just over 3 hours…

8. 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  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

9. 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.

10. What Causes Increased Hazard?  A wet season, followed by dry season  Brush fires are fiercest when there is lots of dried brush for fuel  A wet spring tends to increase the fire hazard  If a dry autumn follows, that leaves lots of dried brush, ready to burn  A wet season, followed by dry season  Brush fires are fiercest when there is lots of dried brush for fuel  A wet spring tends to increase the fire hazard  If a dry autumn follows, that leaves lots of dried brush, ready to burn

11. 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.