Authorities say smoke from a record wildfire in and around Yosemite National Park in California will continue to affect Northern Nevada through Labor Day weekend.
National Weather Service meteorologist Mark Deutschendorf said the regional air quality will continue to vary depending on fire behavior and wind conditions.
Deutschendorf says the sky may clear at times, only to darken with smoke hours later.
A smoky haze is expected most in Minden, Gardnerville and South Lake Tahoe.
In Yosemite, the smoke hampered both suppression efforts and the prized views sought by holiday weekend tourists.
For the first time since the blaze broke out in a neighboring forest two weeks ago, smoke obscured Yosemite Valley, home to the park’s most popular landmarks, spokeswoman Kari Cobb said.
“I’m in Yosemite Valley right now, and I cannot see the cliffs around me,” Cobb said. “The wind has shifted and smoke is impacting the entire park. We have been lucky until now.”
All the campgrounds in the Valley still were full as of Saturday morning, despite the thick blanket and burning smell that permeated the area and was expected to linger until at least Monday, she said.
As a health precaution, visitors were being asked to scale back their outdoor recreation plans and avoid strenuous activities or even stay indoors.
Meanwhile, firefighting aircraft were grounded most of the morning because of low visibility caused by the smoke, U.S. Forest Service spokesman Mark Healey said. The blaze had scorched 343 square miles of brush, oaks and pines and 11 homes, as of Saturday, an area larger than the cities of San Francisco, Oakland and San Jose combined.
Of that total, 94 square miles of wilderness have burned in the northern section of Yosemite, up from 75 square miles a day earlier.
The cause of the fire, which started and has claimed the most acreage in the Stanislaus National Forest, is under investigation.
Healey said fresh firefighters were being brought in to replace tired crews, but that officials did not plan to reduce the nearly 5,000 people assigned to the blaze.
The wildfire is the largest now burning in the United States and is the fifth-largest in California history.