Firefighters are gaining ground on the aggressive Blue Cut wildfire in Southern California's San Bernardino National Forest that has destroyed nearly 100 homes and more than 200 other structures.

It's one of several major fires impacting the drought-stricken state. And as NPR's Kirk Siegler tells our Newscast unit, hundreds of the 80,000 put under evacuation notice are now cleared to return home, but "controlling a blaze like this will take weeks." He explains:

"Just to get an idea of what crews are up against to contain it, imagine having to dig a large trench or fire line all the way around the perimeter of a city the size of San Francisco, and then keep a fire from spreading outside it. Firefighters are hoping to take advantage of some calmer winds that are in the forecast over the weekend."

The fire is still raging over more than 30,000 acres and is 40 percent contained, with 1,584 firefighters battling the blaze, according to the National Wildfire Coordinating Group.

It erupted Tuesday, and San Bernardino Fire Chief Mark Hartwig said it "moved with intensity and ferocity that firefighters haven't seen before," as member station KPCC reported. Here's more from KPCC:

"During five years of drought, California's wildlands have seen a continuous streak of destructive and sometimes deadly fires. No deaths have been reported in the latest fire, but crews assessing property damage were using cadaver dogs during searches."The dry vegetation is like firewood, said fire information officer Sean Collins."

The firefighters' efforts were complicated by a large number of people put under mandatory evacuation notice that didn't leave their homes, as NPR's Nate Rott reports. "Fifty percent of the people are not evacuating," Bob Poole of the San Bernardino Forest tells Nate. "We can't do much about it but tell them that it's in their best interest to leave." He adds that people often "change their minds when the flames reach their yard."

As Nate points out, Southern California residents have grown accustomed to wildfires. "Almost every homeowner you talk to here and in Southern California can remember the last big wildfire or the last time they were told to evacuate," he reported.

Another fast-moving wildfire in California's Lake County this week destroyed 300 structures, as The Los Angeles Times reported.

"They are just moving as fast as the wind can push them and that's leading to what we're seeing in terms of devastation," Pomona College professor and wildfire expert Char Miller told the Times, speaking about both fires. "Let's call it an imperfect storm of conditions: the drought, the heat, the low humidity. And let's be honest, this is not really big winds."

Meanwhile, California firefighters battling the flames are calling for reinforcements from neighboring states, as KPCC's Emily Guerin tells our Newscast unit.

"When lots of fires are burning at the same time, and most of Cal Fire's crews are on the front line, the agency turns to the National Interagency Fire Center in Boise, Idaho for more manpower," she says.

Guerin reports that "the Southwest and the Rocky Mountains are wetter and have fewer fires than Southern California," according to Robyn Broyles from the center. "So, we would go to those parts of the country to ask for assistance first, because we don't want to take resources away from parts of the country that are already needing them," Broyles says.

Meanwhile, as the fire is further contained, area residents are beginning to assess the damage to their homes.

Johanna Santore was out running errands when the fire erupted, and then tried to "rescue the family's four dogs, six cats and hamster but was blocked by closed roads," as The Associated Press reported.

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