(CNN) It may take until September to contain the largest fire in California history, which is bigger than the size of the city of Los Angeles.

So far, two firefighters have been injured while fighting the Mendocino Complex Fire, which consists of the Ranch and River fires -- in Northern California. The two have burned 302,086 acres and were 47% contained as of Wednesday evening.

The colossal fire altogether has destroyed 119 residences, according to the California Department of Forestry and Fire Protection, known as Cal Fire.

Cal Fire estimated that full containment could take until September 1. The Mendocino Complex Fire ignited on July 27.

Last year's Thomas Fire, which is the second-largest fire in California history, took more than six months to extinguish after burning 281,893 acres in Ventura and Santa Barbara counties.

Firefighters in the state are battling 15 large fires.

Arrest made in connection with Holy Fire

About 20,000 residents are under a mandatory evacuation as the Holy Fire grows in Riverside County, according to Thanh Nguyen with the SoCal Team One Fire Management Team.

Meanwhile, a man has been arrested in connection with the Holy Fire, which forced mandatory evacuations near the border between Orange and Riverside counties in Southern California.

Forrest Gordon Clark, 51, was being held at the Orange County Jail on Wednesday on suspicion of two counts of felony arson, a count of felony threat to terrorize and misdemeanor resisting arrest, the Cleveland National Forest said via Twitter. The charges being leveled could carry a life sentence, said Susan Schroeder of the Orange County District Attorney's Office.

Clark, who is being held on $1 million bail, was expected in court on Thursday. The fire at Holy Jim Canyon started Monday, and has burned 6,200 acres and is 5% contained, officials said.

Trump weighs in on wildfires

This week, President Donald Trump appeared to blame California's environmental protection laws for the cataclysmic fires. Administration officials declined to offer any clarity on Trump's series of tweets.

Trump claimed the fires were being "made so much worse by the bad environmental laws which aren't allowing massive amount of readily available water to be properly utilized." He also added that water in the state was "being diverted into the Pacific Ocean" in a tweet that named California Gov. Jerry Brown.

Governor Jerry Brown must allow the Free Flow of the vast amounts of water coming from the North and foolishly being diverted into the Pacific Ocean. Can be used for fires, farming and everything else. Think of California with plenty of Water - Nice! Fast Federal govt. approvals. — Donald J. Trump (@realDonaldTrump) August 6, 2018

"This does not merit a response," said Evan Westrup, a spokesman for the Democratic governor.

What's fueling fires?

Environmental scientists, California water experts and local officials have disputed Trump's claims.

"It is climate change that is causing this," said Michael Mohler, spokesman for Cal Fire. "There is no other way to explain explosive fuel conditions that come with increased winds and higher temperatures."

California's multiyear drought ended last year, but it left a lot of dried and weakened plants and trees.

"You don't recover from six years of drought overnight," Mohler said.

California has more than 100 million dead trees due to drought and infestation from bark beetles. Dead trees pose a major hazard as they allow wildfires to spread rapidly in hot, dry conditions. Cal Fire's vegetation management crews are out year-round to thin and remove such trees while also doing prescribed burns.

About $70 million of ongoing resources have been added to the state budget in the past four years to provide additional fire suppression resources, according to Ali Bay, spokesman for the governor. Approximately $800 million has been added for projects focused on the prevention of forest fires, including more fire prevention inspections and projects, removal of dead trees and other fuel reduction activities and projects.

Experts also cite hotter temperatures causing lengthier fire seasons that burn up dry, dead vegetation as factors for more wildfires.

This past July was California's hottest month on record, topping the previous record that had been set in July 1931, according to the National Oceanic and Atmospheric Administration. The three biggest fires currently burning in California all started in July.

Climate change has increased the length of fire season, said Malcolm North, research scientist for the US Forest Service Pacific SW Research Station.

"Now they are pretty much combustible year-round," said North, who is also an affiliate professor at UC Davis.

"With climate change, we pretty much know there will be an increase in extreme fire weather. After winds get to 35 mph, you are at the mercy of the fire."

Other fires in the state continue

Cal Fire reported that warm temperatures, with highs in the 90s and triple digits, are expected in most areas of the state -- which isn't good news for firefighters. But a slight cooling is forecast for the weekend.

More than 14,000 firefighters are battling the wildfires across the state.

The second biggest fire is the Carr Fire in Shasta County in the northern part of the state.

The deadly blaze has been burning for more than two weeks and consumed 176,069 acres as of Wednesday. It has killed seven people and destroyed more than 1,100 homes.

The next largest one is the Ferguson Fire, near Yosemite National Park, with 94,992 acres. That fire has lasted more than three weeks and killed two people.