Rim Fire Closes Roads into Yosemite ahead of Labor Day Weekend

California's Rim Fire continues to burn in Yosemite National Park and Stanislaus National Forest, gaining more than 20,000 acres in size since Tuesday, yet fire-fighting crews have been able to maintain pace in keeping the blaze under control, with the latest data indicating the fire is 23 percent contained.

Now standing at 187,466 acres, the Rim Fire is the largest wildfire in California since 2007 according to data from the Cal Fire website. According to Reuters the blaze is the sixth-largest in state history.

The Rim Fire, which is the largest active wildfire in the nation, burns primarily in the Stanislaus National Forest, but it has scorched more than 40,000 acres of Yosemite National Park, according to Reuters, which also reported that a major road into Yosemite will close Wednesday, limiting access to those wishing to visit the park over Labor Day weekend.

Yosemite spokesman Tom Medema told Reuters that at noon local time on Wednesday the second of four access roads to the park will close to allow fire crews to build containment lines to keep the blaze from encroaching further into the park.

"That will limit the access for visitors to and from the east side of the park, quite possibly over Labor Day weekend, which will have a significant economic impact on the area and an inconvenience for visitors," he said.

While tens of thousands of acres have burned in the national park, the Yosemite Valley, a popular tourist destination and home to iconic landmarks such as El Capitan and the Halfdome rock formations, remains unaffected and open to the public.

At least 10 wildfires are currently burning in California at the peak of its wildfire season, but the Rim Fire is demanding the most resources, requiring numerous fire-fighting airplanes and helicopters to assist nearly 4,200 crew members battling the blaze on difficult terrain.

The Rim Fire has cost the state of California more than $20 million, the San Jose Mercury News reported on Tuesday, adding that President Barack Obama promised federal resources help fight the fire.

Outlook for containing the blaze will largely depend on the weather. Cool temperatures, high humidity and calm winds will were a boon firefighters overnight into Wednesday, enabling them to establish more containment lines. But humidity is expected to drop to 15 percent and temperature is forecast at a high of 94 Fahrenheit (34 Celsius) on Wednesday afternoon.

"If we reach the maximum temperature and the minimum humidity, we're expecting continued erratic fire behavior," California Department of Forestry and Fire Protection spokeswoman Alison Hesterly said, according to Reuters.

The official Inciweb online fire information system reports that approximately 4,500 structures remain threatened in advance of the Rim Fire to both the east and the west. at risk from the Rim Fire. Several area residents are under mandatory evacuation orders, with evacuation advisories in place for a ten mile stretch of land in the Stanislaus National Forest between the towns of Long Barn and Pinecrest.