CNN — (CNN) -- Crews battling the Arizona wildfire that killed 19 firefighters have it 80% contained, a fire official said Friday.
But deputy incident commander Jerome Macdonald also told reporters that he suspects it will be at least another week before the Yarnell Hill Fire near Prescott is 100% contained.
Often "that last 20%, it's not as easy to get it to that level," he said, and there is still work ahead to make sure all is safe.
The Yarnell Hill fire was started by lightning June 28 and is burning approximately 30 miles southwest of Prescott off Highway 89, according to Inciweb, a federal website that disseminates information from agencies like the U.S. Forest Service and Bureau of Land Management.
Temperatures hovered in the mid-80s as crews fought the blaze and inspected gas storage tanks to make sure they are safe.
Some of the tanks are owned by gas companies while some are privately owned, Macdonald said. Crews are checking every one, securing them and marking them "OK" as they go through.
On Thursday, news that the fire was diminishing was met with relief on an official Facebook page dedicated to news about the blaze.
"Praise the Lord!" one person post wrote.
The Yavapai County Sheriff's Department has lifted an evacuation order for residents of Peeples Valley, according to Inciweb. Those who live in the community of Yarnell are still under a mandatory evacuation order.
On average, workers have been putting in 13- or 14-hour shifts but are able to sleep, shower and eat when they need to, U.S. Forest Service spokeswoman Suzanne Flory said Thursday. "We're very safety conscious and we're very careful about not overstressing or overworking anybody and making sure they get that rest that they need."
Four helicopters were battling the blaze Thursday, she told reporters.
Temperatures reached into the 90s on Thursday, with winds gusting in excess of 20 mph. It was still windy Friday, and the predicted high was 91, but the thermometer was staying in the 80s during the morning. The National Weather Service is showing showing thunderstorms possible Friday to Monday.
Rain would be welcome in many ways, though thunderstorms also bring the possibility of lightning that could spark more fires. And wet conditions could also hamper efforts because people could get stuck in mud, explained National Weather Service meteorologist Jim Wallman.
The Maricopa County medical examiner's office performed autopsies on the 19 firefighters and said Thursday they died of "fire-related injuries" as a result of an accident.
Plans to remember the firefighters include a memorial service scheduled for Tuesday in Prescott Valley. Vice President Joe Biden will attend, a senior administration official told CNN Friday.
The ceremony is expected to begin at 11 a.m. at Tim's Toyota Center, according to CNN affiliate KPHO.
On Wednesday, nearly 600 firefighters and support workers assigned to the fire took a brief break from their hard work to observe a moment of silence in honor of the members of the Granite Mountain Hotshots, who died Sunday when the fire took a sudden, unexpected turn.
The pause coincided with the movement of a convoy of vehicles driven to the fire by the Granite Mountain team. The vehicles are being returned to Prescott, where the team was were based.
To start Wednesday's moment of silence, a loud alert tone sounded on firefighters' radios and an unidentified fire team commander announced, "As the crew carriers for the Granite Mountain hot shots leaves the Yarnell Hills fire and begin their journey home, all personnel in the incident will observe an operational pause, in observance of our fallen comrades."
The bodies are being guarded by members of the Phoenix Fire Honor Guard at the medical examiner's office in downtown Phoenix, the affiliate reported Thursday.
In an unrelated incident in California, a firefighter was fatally injured Friday morning when a passing car struck him while he was working along Interstate 10 in the Thousand Palms area of Riverside County, the California Department of Forestry and Fire Protection said. The identity of the fire apparatus engineer wasn't released, pending notification of relatives, the agency said.