A Carlsbad, Calif., police officer turns traffic away as flames leap behind him on May 14, 2014.
A combustible combination of record heat, intense drought and powerful and desiccating Santa Ana winds has helped fuel several wildfires in California. On Wednesday, fire crews battled a rapidly spreading 100-acre wildfire in Carlsbad, California, about 35 miles north of San Diego. At 1 p.m. PT, conditions in Carlsbad were ideal for supporting a growing fire, with wind gusts near 30 miles per hour, a temperature of 100 degrees Fahrenheit, and just 3% humidity.
According to NBC 4 News in Los Angeles, the AlertSanDiego system called at least 11,600 homes, businesses and cell phones to instruct people to evacuate. The fire began at 10:40 a.m. P.T. "and moved quickly," according to NBC 4. The network isreporting at least five major fires burning in San Diego County, with multiple homes on fire in Carlsbad, California.
Other fires have erupted near Camp Pendleton in San Diego County, and a fire southwest of Rancho Bernardo has burned at least 1,500 acres, according to CalFire.
Officials were opening shelters for evacuees of the Carlsbad blaze, known as the Poinsettia Fire, and evacuations have been ordered near Camp Pendleton as well.
Santa Ana Winds have brought record heat to much of southern and central California this week, with wind gusts in hilly areas reaching close to 90 miles per hour, as temperatures have soared above 100 degrees Fahrenheit in many areas. In San Diego, which is typically cooled by onshore winds off the Pacific Ocean to the west, the strong Santa Ana winds from the east have resulted in some of the hottest May temperatures on record since data began in 1896.
CAL FIRE is assisting Carlsbad Fire with a 100 acre wildfire off Poinsettia Ln & Alicante Rd in Carlsbad (San Diego County) #PoinsettiaFire— CAL FIRE (@CAL_FIRE) May 14, 2014
According to the National Weather Service (NWS) forecast office in San Diego, two days so far this May have ranked among the top eight hottest May days on record. The forecast high of 97 degrees Fahrenheit on Wednesday is just one degree shy of the all-time high temperature record for May, which was set on May 25, 1896. The forecast high temperature of 95 degrees Fahrenheit on Thursday would rank among the top five hottest days in May, the NWS said on its website.
The heat poses a health risk, particularly to the elderly, people on certain medications and the very young. Extreme heat is the leading weather-related cause of death in the U.S., and is expected to worsen as global warming results in more frequent and intense heat waves.
According to the NWS in Los Angeles, the fire danger will remain high through Thursday, before cooler air moves in.
"The combination of gusty Santa Ana winds, hot temperatures and single-digit humidities will bring extreme fire danger to the region through mid-week," the NWS said.
Unusual heat and high fire risk is also affecting Silicon Valley, where temperatures are above 100 degrees Fahrenheit, and San Francisco, where temperatures rarely get above 90 degrees but did so on Tuesday and are expected to again on Wednesday and Thursday.
California is in the grips of an intense drought, with 25% of the state experiencing "exceptional" drought, which is the worst category on the U.S. Drought Monitor. The entire state is experiencing moderate drought conditions or worse, with little to no relief expected until the fall. This does not bode well for the rest of wildfire season.