The fire started at about 3:13 a.m. on October 23 as a structure fire on the La Jolla Indian Reservation and has then moved itself onto Palomar Mountain. It is running in the same way as the Rice Fire. With firefighters worried that the Rice Fire and Poomacha fire will meet in the Del Dios Canyon, firefighters have left the area and people living there have to leave.
The Rice Fire is burning in the Rice Canyon near Fallbrook, moving towards Rainbow Heights, and Santa Marguerita and Sandy Creek drainages.
As of 12:20 a.m. PST on October 23, the US Forest Service was thinking the Ranch, Buckweed, and Magic fires would meet into a single huge fire within 2 days.
Current data on the fires has been provided by the California Department of Forestry and Fire Protection, although the chaotic nature of the fires meant not all information was available. As of October 23 at 11:34 a.m. PST:
As of 23 October 2007 the Buckweed fire in Agua Dulce and the Santa Clarita community of Canyon Country has burned in northeastern parts of the county. The communities of Santa Clarita, Leona Valley, Green Valley, Acton, Agua Dulce, and Mint Canyon are in danger. At least 925 firefighters are fighting the fire. Over 15,000 people and 5,500 homes have been evacuated.
The Canyon Fire has burned close to Malibu, California, mostly in Malibu Canyon. 600 residences, 200 commercial buildings, and 100 outbuildings are in danger, and 500 homes have been evacuated.
The Magic Fire started near The Old Road at Magic Mountain Parkway. Flames crept a few yards from West Ranch High School and a many houses being made in Stevenson Ranch, but were pushed away. The fire is believed to have been caused accidentally by welders at a construction site.
The October Fire burned a small area in Santa Clarita, burning several homes in the Canyon Breeze Mobile Home Park.
Since 20 October 2007, the Ranch fire has burned on the Los Angeles-Ventura county line, in the Angeles and Los Padres national forests. The fire is going around the Ventura County community of Piru and also threatens the communities of Fillmore, Ventura and Ojai. Three homes have been destroyed, and 500 residences are in the fire's path. As of 7:00 a.m. local time, the fire was 10% under control. Evacuations have been recommended in all of Piru and parts of Fillmore. Highway 126 is closed between Main Street and Chiquita Canyon Road in Piru. Angeles National Forest officials are closing the whole forest, starting October 23.
The Santiago Fire began shortly before 5:55pm on October 21, 2007 in the foothills north of Irvine and east of the city of Orange in Orange County. Fire officials have said that the source of the fire is arson; the fire was said to have been started in three different spots. The fire has burned over and is 30% contained. Strong winds have stopped people from fighting the fire and forced a dozen firefighters to seek emergency shelter under tents after the fire moved at them. Two homes, one mobile home, and one outbuilding have been destroyed. Several other buildings damaged, and four firefighters were a bit hurt from the fire. Damage estimates put the fire's cost at $5.5 million.
Current data on the fires has been provided by the California Department of Forestry and Fire Protection, although the chaotic nature of the fires meant not all information was available. As of October 23 at 11:34 a.m. PST:
The Slide Fire has burned at Green Valley Lake, west of Lake Arrowhead. The Green Valley Lake, Arrow Bear, and Running Springs communities are under evacuation. Reports indicate water pressure in local systems was lost and conditions were too harsh for fighters to continue efforts in some areas. The fire has burned a camp owned by the Boy Scouts of America's local council, the California Inland Empire Council, called "Camp Helendade." Helendade was originally given to the council in 1960 to replace another camp that had been burned.
The Grass Valley Fire is burning just north of Lake Arrowhead. An online appeal from firefighters near the blaze at Lake Arrowhead showed that resources were spread thin:
"Immediate threat to 100 structures and possible threat to thousands ... Multiple downed power lines. IC (Incident Command) asking for resources from anywhere ... Lack of resources hindering suppression efforts. Unable to fly aircraft. All local engines are depleted."
The fire began near Martin Ranch Road and Meyers Road.
This fire was in the Ontario, California area. It damaged several buildings.
Together the fires made it a must to close Interstate 15 in the Cajon Pass. One fire was started by an flipped-over semi-truck. This fire has burned 250 acres. It is currently 50 percent under control. 107 firefighters are assigned to this fire.
The Little Mountain fire threatens several homes and other structures.
The Sedgewick Fire was the farthest north of the October 2007 California wildfires. It started around 6:00 a.m. PST on October 21, 2007 from a falling power line. The fire burned a total of near Los Olivos. Approximately 2000 people were affected and 800 homes threatened before the fire was all under control around 5:00 p.m. on October 22.
The Roca fire began at 3:52 p.m. on October 21 in Aguanga, and burned east of Temecula. The fire was 100% contained on October 22. One home was destroyed and one injury was reported from the fire.
The Rosa fire began at 11:00 p.m. on October 22 in western Temecula and has burned . There are people who have to leave and closed roads in this area. The fire is 50% under control; 100% expected by October 24 at 6 p.m.
The fires are occurring in a very dry area and they are being exacerbated by seasonal winds called the Santa Ana winds. The San Diego Union Tribune reported, "Santa Ana winds blowing up to 60 mph combined with temperatures into the 90s to create in the worst possible fire conditions."
Southern California is in the midst of an unusual drought; in Los Angeles, California, with only 3.21 in (82 mm) of precipitation in the entire 2006-2007 rain season, it is the driest year on record, receiving less rain than Death Valley in a normal year.
The Santa Ana winds are warm, dry winds that characteristically appear in Southern California and Northern Baja California weather during autumn and early winter. Santa Anas are a type of föhn wind, the result of air pressure buildup in the high-altitude Great Basin between the Sierra Nevada and the Rocky Mountains. This high energy wind spills out of the Great Basin and is pulled by gravity into the surrounding lowlands. The air circulates clockwise around the high pressure area bringing winds from the east and northeast to Southern California (the reverse of the westerly winds characteristic of the latitude). The air heats up due to adiabatic heating while being compressed during its descent. While the air has already been dried by orographic lift prior to reaching the Great Basin, the relative humidity of the air declines rapidly as it descends and warms in its final stages as it passes over the Transverse and Peninsular Ranges.
The air is then forced down the mountain slopes out towards the Pacific coast; the air mass is further heated by compression as it drops in altitude before reaching the Los Angeles Basin, western San Diego County and Tijuana (Baja California) at typical speeds of 35 knots. The southern California coastal region gets some of its hottest weather of the year during autumn while Santa Ana winds are blowing. During Santa Ana conditions it is typically hotter along the coast than in the deserts and the humidity plummets to less than 15%.
As the Santa Ana winds are channeled through the mountain passes they can approach hurricane force. The combination of wind, heat, and dryness turns the chaparral into explosive fuel for the infamous wildfires the region is known for. Wildfires fanned by Santa Ana winds burned 721,791 acres (2,921 km²) in two weeks during October 2003.