SOUTH LAKE TAHOE, Calif. — Weather was favorable on Wednesday for firefighters as spread of the Caldor Fire slowed.

The uncontained blaze is burning between Grizzly Flat and U.S. Highway 50 and has chewed up 65,475 acres.

The smoke that caused hazardous air quality in the Lake Tahoe Basin on Tuesday, let up a bit on Wednesday as the day progressed.

Eric Schwab, Cal Fire operations section chief, said during a Wednesday evening briefing that the red-flag northern winds predicted for Wednesday “haven’t made themselves known, which is a huge help for us.”

He added that an inversion layer also “sat over the fire for the day, dampening fire behavior,” according to Schwab.

That break from what firefighters have described as extreme fire activity — about 47,000 acres burned Tuesday — has allowed crews to scout where they will put in control lines to stop the spread of the fire.

The Caldor Fire has been burning for five days, destroying structures in Grizzly Flat and evacuating thousands of area residents.

Schwab said firefighters did a lot of field preparation for a control line along the entire eastern flank of the blaze.

Schwab noted flames are about 1.5 miles from Sly Park Road and hundreds of yards from Highway 50 south of Ice House Road.

On the southwestern perimeter of the Caldor Fire, Schwab described the three river drainages of the Cosumnes River as having “geographical challenges.” Building containment lines there “is not conducive,” he explained. “We cannot be successful in going directly against the fire in that steep terrain. It won’t hold.”

Instead firefighters will use topographical features to their advantage to curb the flames.

Cal Fire Incident Commander Dusty Martin joined in a virtual community meeting hosted on Facebook Wednesday night.

“We still have an extremely active fire. Our No. 1 priority is to get the community back open and each and every (resident) back into their homes. We cannot do that until it is safe to do so — safe for firefighters and safe for the public,” he said.

Cal Fire’s incident management team said a fire spotted 5 miles to the east amid “normal” wind conditions Tuesday.

The fire made runs in steep drainages Wednesday, aided by dry vegetation. The fire’s most significant growth was in the northeast corner south of Highway 50, but Cal Fire officials say there was some movement on all sides.

Martin said damage assessment of fire-impacted areas could take a week or more.

Meanwhile, fire resources are holding at Ice House and US 50.

“It’s a huge priority of mine to keep the fire on the south side of Highway 50,” Schwab said.

Total personnel fighting the fire grew from about 240 on Tuesday to more than 600 on Wednesday as resources from the record-setting Dixie Fire, that is about one-third contained, were transferred to battle the Caldor Fire, according to an Associated Press report.

There are 61 engines, 10 water tenders, 11 hand crews and 20 dozers working the blaze.

The El Dorado County Sheriff’s Office is patrolling evacuated areas focusing on preventing looting, said Sgt. Eric Palmberg.

“We are conducting enforcement and we have adequate resources thanks to multiple agencies,” he said.

The Mountain Democrat’s Kryten Kellum contributed to this report.