By Alex Dobuzinskis
LOS ANGELES (Reuters) - A heat wave baking much of California posed difficulties for crews battling several major wildfires across the state on Wednesday, the largest threatening dozens of homes near Kings Canyon National Park as residents braced for possible evacuations.
Temperatures in excess of 100 Fahrenheit (38 Celsius) settled over large parts of the state on Tuesday and were expected to persist until Thursday, National Weather Service meteorologist Carol Smith said.
The port city of Long Beach, just south of Los Angeles, posted a record-high temperature for the date on Wednesday of 103F (39C), Smith said.
Areas of Los Angeles' sprawling San Fernando Valley also sweltered in temperatures above 100 F (38 C), she said.
While the extreme heat was uncomfortable for many California residents, it presented more acute risks for firefighters wearing heavy gear and struggling to suppress at least five large wildfires or clusters of fires statewide.
The so-called Rough Fire, which ranks as the largest blaze in California and has charred more than 103,000 acres (41,500 hectares) of drought-parched timber, chaparral and tall grass since it was ignited by lightning on July 31 east of Fresno in Kings Canyon National Park.
Temperatures in parts of the fire zone topped 100F on Wednesday, said Jake Rodriguez, a spokesman for the team managing the blaze.
Some 1,900 firefighters, laboring in steep, rocky terrain, were assigned to the fire and as of Wednesday had managed to carve containment lines around 31 percent of its perimeter, Rodriguez said.
"Heat is an extremely difficult factor to work around, there's really no way around it," he said. "They just have to make sure that they stay hydrated."
The blaze has cast smoke over numerous hiking and camping areas, prompting cancellations of activities. All campgrounds in Kings Canyon National Park were closed for the Labor Day weekend and remained closed on Wednesday.
On Tuesday, authorities alerted residents of dozens of houses in some of populated areas near the fire zone, including the community of Dunlap, that they may need to evacuate at a moment's notice, said Tony Botti, a Fresno County Sheriff's Office spokesman.
Those advisories remained in place on Wednesday. At least a dozen homes near the fire were evacuated on Monday.
Firefighters in six Western states - California, Oregon, Washington, Idaho, Montana and Utah - were contending with a total of 35 large wildfires on Wednesday, according to the National Interagency Fire Center in Idaho.
(Reporting by Alex Dobuzinskis; Editing by Steve Gorman and Eric Beech)