Rim Fire continues to inch toward Yosemite's giant sequoia groves

YOSEMITE NATIONAL PARK, CA - AUGUST 25: Trees burned by the Rim Fire stand on August 25, 2013 in Yosemite National Park, California. The Rim Fire continues to burn out of control and threatens 4,500 homes outside of Yosemite National Park. Over 2,000 firefighters are battling the blaze that has entered a section of Yosemite National Park and is currently 7 percent contained. (Photo by Justin Sullivan/Getty Images)

Officials say the Rim Fire is 20 percent contained, but fire crews are optimistic that cooler temperatures and higher humidity will help. As the fire rages on the edges of Yosemite National Park, one of California's oldest and greatest natural treasures is under threat.

The massive wildfire burning in northern California grew to about 280 square miles this morning.

Officials say the Rim Fire is 20 percent contained, but fire crews are optimistic that cooler temperatures and higher humidity will help. As the fire rages on the edges of Yosemite National Park, one of California's oldest and greatest natural treasures is under threat.

The fire is growing dangerously close to two of Yosemite's three groves of Giant Sequoias.

John Buckley is the executive director of the Central Sierra Environmental Resource Center. He also spent 13 years as a U.S. Forest Service firefighter in the area.

Remembering The 1988 Yellowstone Fires

The Rim fire's rage comes exactly 25 years after a summer of wildfires tore through Yellowstone National Park. More than a third of Yellowstone was scorched. With more on what that massive fire has taught fire managers is Al Nash, spokesman for Yellowstone.