Fires are “not yet” as severe as those of 2003, when the Cedar Fire alone caused losses of $1.2bn

According to AIR Worldwide, fierce winds continue to fuel wildfires that have been scorching seven southern California counties since the weekend.

These blazes, which number more than a dozen, have destroyed nearly 1,500 homes and businesses, forced some 300,000 residents to evacuate their homes, and burned approximately 260,000 acres—more than 400 square miles.

The large number of separate fires has effectively diluted fire suppression activities and firefighters have thus far been largely ineffective in containing them. High winds, low humidity and high temperatures continue to fuel advancing flames.

Some relief may be in store for the region, as an extremely strong surface high-pressure system (1040 mb) located over the Northern Great Basin (Southern Idaho/Northern Utah) is forecast to weaken today and tomorrow and move eastward as a low-pressure system approaches the Pacific Northwest.

But in the meantime, the pressure difference between these two systems is producing very windy conditions over southern California—conditions that are expected to persist into Wednesday.

"Further, the winds are accompanied by anomalously hot temperatures and dry air as the flow descends and compresses from the already dry high desert located east of the Los Angeles basin," said Glen Daraskevich, vice president of research and modelling at AIR Worldwide.

"This is the classical Santa Ana wind condition, but with extremes on all counts—producing very high winds, very warm temperatures, and very dry air—all of which exacerbate the spread of wildfires. One observation from Fontana, CA yesterday indicated the dew point there had dropped to -22 degrees F, resulting in an almost unheard of relative humidity of 2%."

San Diego County faces the most severe conditions. More than 250,000 residents there have been evacuated, some 10,000 of them to Qualcomm Stadium.

Major fires are also burning in Los Angeles County, where some 2,900 fire-fighters have made minimal headway containing them. And new fires are cropping up. Early Tuesday, officials reported a fresh fire on the La Jolla Indian Reservation. It has consumed 1000 acres, destroyed several structures and forced the evacuation of more than 1,500 people.

"With more than 1,000 homes destroyed so far, the fires of 2007 are not yet as severe as those of 2003, when the Cedar Fire alone destroyed more than 2,200 homes and resulted in insured losses estimated at $1.2bn," continued Daraskevich. "However, many of the current fires burn unabated and the potential exists to exceed the Cedar Fire both in terms of the number of structures destroyed and total insured losses."