Yosemite’s Washburn Fire Tripled in Size Over the Weekend

A fire that ignited dangerously close to Yosemite’s Mariposa Grove on July 7 tripled in size between Saturday and Sunday, growing from about 700 acres on Saturday morning to about 2044 acres by Sunday evening. As of Tuesday afternoon, the fire was reported to be about 3220 acres in size. But Yosemite’s largest trees are still safe—for now.

According to Lee Beyer, a Public Information Officer on the Washburn Fire, the growth of the fire has been steady, “but not fast.” 

“There is a significant deep fuelbed of both fallen and dead standing trees, needles and forest debris,” he said. “Ember cast is resulting in spot fires which is making control challenging” So far, authorities say there have been no injuries or casualties

The U.S. government first protected Mariposa Grove in 1864 under an order signed by President Abraham Lincoln. The protection preceded Yellowstone National Park’s designation by 8 years. 

In 1906, Mariposa Grove became part of Yosemite National Park. It’s now the park’s largest sequoia grove, with more than 500 trees, some of them estimated to be over 2,000 years old. Two trees in the grove are among the largest sequoias on Earth.

The Washburn Fire entered the Mariposa Grove last week, but previous prescribed burns and the clearing of debris in the area has created a donut-like barrier around the large trees. None have burned at this time.

To combat potential damage to historical sites and many of the park’s sequoia trees, firefighters installed a sprinkler system to dampen the ground and placed around the Galen Clarke Cabin as a deterrent. 

“While structure wrap is not currently being used on the giant sequoias, firefighters are proactively protecting the Mariposa Grove through the use of a ground-based sprinkler system,” the National Park Service stated in a release:  This increases the humidity in the area around the trees and combined with the removal of ground fuels, the ground fire risk is greatly reduced.” 

Over 700 fire personnel are currently battling the blaze, along with a number of aircraft. The fire has produced some updrafts so powerful that they’ve blown branches and other debris hundreds of feet in the air, causing them to fall on tankers battling the fire.

The release adds that the terrain in the region creates dangerous obstacles for the firefighters. Standing dead trees pose a potentially deadly risk, and steep terrain has made the firefighters’ task more difficult. A predicted warming trend could also increase the severity of the fire.

While the cause of the fire is still under investigation, dried vegetation in the area likely created an accelerant. There also aren’t a lot of natural barriers like roads in this part of the park to prevent the fire from expanding. The fire is currently about 22% contained.

With their sheer mass and height, giant sequoias can seem indestructible. But this isn’t the first fire to pose a threat to them: Last year, fires destroyed about 3,600 sequoias, and in 2020, Sequoia National Park’s Castle Fire destroyed about 10% of the worldwide population of the species. In the past 3 years alone, blazes have destroyed 19% of the sequoia populations. But fire entering a sequoia forest isn’t necessarily a death sentence for the trees: Sequoias have been known to be able to withstand heat, which could prove vital in their survival during the Washburn Fire. 

In addition to threatening iconic park destinations like the Mariposa Grove, emergency personnel have evacuated residents of Wawona and visitors to the Wawona Campground. The town, which has a population of just under 200 people, is home to the historic Wawona Hotel. 

Aside from the southern entrance and the region of the park that’s being threatened by the fire, the rest of Yosemite National Park remains open to visitors. Officials warn that the remaining entrances in the park may experience higher levels of congestion, and that unhealthy air quality could negatively impact the park experience.