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California wildfire more than triples in size, jumps containment line: AIR Worldwide


August 5, 2015   by Canadian Underwriter


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Catastrophe modelling firm AIR Worldwide reported on Tuesday that the Rocky Fire wildfire in northern California has more than tripled in size over the weekend and then jumped a containment line on Monday, as it grew to 97 square miles (more than 25,000 hectares in size).

The Rocky fire still burns south of Clear Lake in Yolo County early Monday morning (Genaro Molina / Los Angeles Times)

The wildfire in the Lower Lake area of California, about 100 miles north of San Francisco, is the largest of nearly two dozen wildfires currently burning in the state — an unusually large number of occurrences for early August, AIR Worldwide said in a press release. The wildfire has destroyed two dozen homes and prompted authorities to either evacuate or warn over 13,000 people.

More than 3,000 fire personnel are involved with Rocky Fire, including crews from outside California, AIR Worldwide reported. Fuelled by tinder-dry manzanita shrubs and other drought-dry brush on steep, rugged hills with limited access, the wildfire has challenged fire crews attempting to build fire lines and control the perimeter.

The California Department of Forestry and Fire Protection (CAL FIRE) added on its website that as of 7:10 a.m. local time on Wednesday, the wildfire, which began on July 29, was 20% contained. A total of 6,959 structures are threatened and 39 residences and 52 outbuildings have been destroyed and four structures damaged, CAL FIRE reported.

Other notable wildfire activity in northern California includes the Mad River Complex, a group of fires caused by lightning on July 30. Located in sharp hills country some 300 miles north of San Francisco, near Ruth Lake, the Mad River Complex has burned more than 20 square miles (5,180 hectares) and currently involves about 600 firefighters.

The Humboldt Lightning Fires complex in Humboldt County in northern California also resulted from lightning on July 30. Consisting of nine primary fires, this wildfire complex has since sparked many smaller fires, burned almost five square miles, destroyed two structures and prompted a limited evacuation (now lifted), AIR Worldwide said in the release. Although fire lines are holding and the fire is 20% contained, the Humboldt Lightning Fires complex threatens 200 structures and poses a threat to commercial timberland, reportedly valued at US$15 million.

In the Modoc National Forest, the Frog Fire, now about 50% contained, remains a threat to power lines, a natural gas pipeline, and a U.S. Forest Service lookout. Caused by lightning, the Frog Fire has burned more than seven square miles.

“Although property damage from wildfires has not been high thus far, the early start to the wildfire season in California, high summer temperatures, and the bone-dry conditions statewide reinforce the high risk for wildfire damage,” AIR Worldwide said in the release. “Already California has experienced more than 4,000 wildfires in 2015, over 50% more than the state’s five-year average.”

In response to the early and high wildfire activity, California Governor Jerry Brown has declared a state of emergency and activated the California National Guard to assist with recovery operations.

According to AIR, wildfire activity increases the risk of erosion in areas with steep, rugged hills. “The barren basins left by the wildfires are subject to precipitation-induced debris flow and associated property damage,” the release said. “Although major precipitation is not expected for Northern California in the coming days, temperatures are moderating, which should help containment efforts for existing fires.”