Firefighters fight to protect redwood trees in California 1:57
(CNN) --
Hot, dry weather conditions are complicating firefighters' efforts to battle a wildfire in California's Yosemite National Park that is threatening a grove of giant sequoias, most of which are more than 2,000 years old.
The Washburn Fire has spread to at least 4,000 acres since it was reported last week and is about 23% contained, according to an update from Inciweb, a national wildfire information clearinghouse, on Wednesday.
The risk to redwoods from wildfires
More than 1,000 fire crew members are battling the blaze, which has spread near the giant sequoias, as well as a small community that had to evacuate last week.
"The more than 500 redwoods of the Mariposa Grove are close to these fires and have so far been spared serious damage from the Washburn Fire," officials wrote in the update.
"Most of these trees are over 2,000 years old and have been burned many times in their lives."
10,000 trees, including giant sequoias, are a danger and must be removed in California, according to authorities
The Washburn Fire made a significant advance to the east on Wednesday.
Temperatures are expected to remain warm and dry through Thursday, with light to moderate winds, creating conditions that could potentially further fuel the fire.
Temperatures will be in the 90s, with relative humidity in the 20% to 30% range, CNN meteorologist Robert Shackelford said.
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"A persistent weather pattern over the next several days will drive active to very active fire behavior in dead and downed heavy fuels," firefighters wrote.
"Continued heat and dry weather over the next several days will lead to further fire growth and smoke production where control lines have not yet been constructed."
Fire threatens Yosemite's Mariposa Grove, home to more than 500 giant sequoias
To protect the 200-foot-tall Grizzly Giant sequoia, fire crews installed a sprinkler system that moistens the ground around it with water from a small pool, which feeds devices installed near the base of the tree, records show. images from Yosemite Fire and Aviation Management.
The cause of the fire has yet to be determined, but park superintendent Cicely Muldoon said earlier this week: "There was no lightning that day, so it's a human-caused fire and it's under investigation."
Wildfires have repeatedly swept through the western US in recent years.
Fires have become more common due to worsening drought conditions caused by climate change.
In California alone, more than a million acres were destroyed in nearly 9,000 fires last year, according to Cal Fire.
More than 1 million hectares burned in Alaska
Meanwhile, more than 1.2 million hectares have already burned in Alaska this season, according to the Alaska Interagency Coordination Center's Wildfire Control Panel.
The state recorded 84 fires this week alone.
"Right now, in terms of acres burned, this is the eighth biggest season since 1950. And I don't think we have records older than that," said Pam Szatanek, a meteorologist with the National Weather Service.
And while next month could bring some relief, Szatanek said that's not a guarantee.
“We are entering a wetter phase, but it is not always consistent that it rains in August when we have a fire season,” he said.
The Upper Talarik Fire destroyed an exploration supply camp in the Pebble deposit area about 17 miles northwest of Iliamna and Newhalen, according to the owners.
The summer work program at the camp had just been completed when the fire broke out over the Fourth of July weekend, Mike Heatwole of Pebble Limited Partnership told CNN.
The fire has burned more than 3,642 hectares, according to the Alaska Wildfire Information Map Series.
Taylor Romine, Paradise Afshar and Jennifer Henderson, all of CNN, contributed to this report.
Wildfires Yosemite National Park