The York fire had expanded to 77,000 acres Monday morning, burning south of Las Vegas, though officials said the spread was slowing.

In an update posted Monday morning on InciWeb, an incident information management system, authorities said firefighters would focus on containment and suppression throughout the day.

“Firefighters saw minimal fire activity last night, along with some precipitation,” the update read. “This means the fire’s intensity and spread were relatively low, which could help in their containment efforts and reducing the risk to property and lives.”

The fire started in the Mojave National Preserve in California around noon on Friday.

Communication, movement and support from planes flying over the fire was limited Monday morning due to visibility of a mile or less in some areas of the fire, authorities wrote. Authorities did not say if it had been contained at all as of Monday.

The fire crossed into Clark County on Sunday, after days of orange haze across the Las Vegas valley. Evacuations had not been announced for Nipton and Searchlight as of Monday morning.

“As always, it’s important to stay updated on official information and follow safety instructions given by local authorities,” the update read. “If you’re in the vicinity of the fire, please take necessary precautions to ensure your safety and the safety of those around you.”

In the Mohave and Castle mountains, Ivanpah and Hart Mine roads, and Walking Box Ranch were closed. Local campgrounds, including Hole-in-the-Wall, Mid Hills and Black Canyon Group and Equestrian Campground also were closed.

Clark County shared this update on Monday morning for residents affected on the Nevada side:

“From an air quality standpoint, smoke from the York fire is only pushing particulate matter into the moderate range. Under current conditions, we are forecasting air quality to remain in that moderate range for particulate matter.

“Right now, our monitoring stations in Boulder City, Henderson and east Las Vegas are showing elevated readings for particulate matter due to the smoke and dust generated by distant thunderstorms blowing directly toward them. Other portions of the valley are also likely to be impacted.

“While the smoke looks nasty and, depending on the time of day and the wind direction it could intensify for periods, the overall air quality picture isn’t as dire as it appears. But particulate matter pollution will fluctuate over the course of a day and can reach elevated levels from one hour to the next, which also may lead to limited visibility at times.

“If you have breathing sensitivities, you may want to take precaution; especially if there are periods of more smoke in the air.”

Contact Sabrina Schnur at sschnur@reviewjournal.com or 702-383-0278. Follow @sabrina_schnur on Twitter.