Oak Fire threatening Yosemite grows to California's largest wildfire this year: What we know

·3 min read

Mariposa County in California remained under a state of emergency Tuesday as the devastating Oak Fire expanded to 28 square miles near Yosemite National Park.

It’s become California’s largest fire of 2022.

But there’s good news – the Oak Fire has not grown significantly this week thanks to ongoing firefighting efforts to tackle the blaze from the air and on the ground, according to the California Department of Forestry and Fire Protection. It is 26% contained.

The Washburn Fire, burning about 7.6 square miles near Yosemite in Mariposa County, remained at 87% containment on Tuesday.

Here's what we know.

Latest update on Oak Fire

Who is affected: The Oak Fire has destroyed 41 structures. No injuries have been reported, according to Cal Fire. It has forced over 6,000 people in Sierra Nevada to leave their homes.

Evacuation orders: They remained in effect Tuesday for several communities near the Oak Fire, with some residents being allowed back in certain areas. Helicopters dropped 300,000 gallons of water over the fire Monday as it moved northeast.

“Fire restrictions and closures near the fire area are in place on the Sierra National Forest,” read a statement from Cal Fire.

Tuesday's forecast may help firefighters

Tuesday forecast: While Tuesday will be mostly sunny with a high of 98 degrees, there’s a 30% chance of showers and thunderstorms in Yosemite Valley in the afternoon, with widespread haze after 5 p.m., according to the National Weather Service.

Showers and thunderstorms to the west of the fire across the Sierra Nevada may be a double-edged sword for firefighters, said AccuWeather senior meteorologist Bob Smerbeck.

“The cloud cover is going to hold the heat down and there will be an increase in humidity,” he told USA TODAY. “Cloud cover and increasing humidity is good for firefighting, but at the same time, lightning strikes can start new fires.”

While smoke appears mostly confined to the Oak Fire site, a smoky haze will drift northward into Northern California and Oregon over the next couple of days, Smerbeck said.

More: Firefighters make progress against California's largest wildfire near Yosemite National Park amid sweltering temperatures

How did the Oak and Washburn fires start?

The Oak Fire ignited July 22 near Midpines in Mariposa County, according to Cal Fire. Agencies are still investigating what caused the fire. It ballooned in size from 60 acres to over 18,000, or 28 square miles, in four days.

The U.S. Forest Service for Sierra National Forest reported that over 2,500 firefighters were working the blaze.

Investigation into what led to the Washburn Fire, which started July 7, is ongoing, but it's thought to be human-caused, according to InciWeb, the national incident information system for wildfires.

A recent warm and dry weather pattern helped crews fighting the Washburn Fire as they worked on what’s called “mopping up” – when firefighters look for remaining areas of heat near the fire’s control lines and extinguish them, according to InciWeb.

In the Northeast: 'Extremely oppressive' heat turns deadly

Wildfires in US: 2 firefighting helicopter pilots die in Idaho; thousands ordered to evacuate near Yosemite

Is Yosemite National Park open?

Yosemite National Park is open to visitors who have a reservation during peak hours, according to the National Park Service. The fire began in Midpines, about 36 miles southwest of Yosemite Valley.

Yosemite’s Wawona community campground, closed due to the Washburn Fire, is expected to reopen to the public Thursday, according to the National Park Service.

This article originally appeared on USA TODAY: Oak Fire near Yosemite is largest wildfire in California: What we know