(CNN) -- A wildfire in Boulder, Colorado continued to burn Friday, but could begin to weaken overnight because of lower temperatures and higher humidity, the local Sheriff's Office said.
Several residential subdivisions on the west side of the city were evacuated earlier as a wildfire spread in Boulder Canyon.
Firefighters had less than 5 percent containment by Friday evening, Boulder County Sheriff's Office Cmdr. Rick Brough told reporters. Some 200 firefighters were scheduled to work on the flames Saturday.
"The expectation is it will start laying down because of the higher humidity and the lower temperatures at night," said Brough. Still, he added the fire has the potential to grow and that much would depend on what area winds do.
The Boulder Dome Fire had burned 144 acres, according to Brough.
The fire was moving north near Elephant Buttress above Dome Rock, said a spokesman with the Colorado Office of Emergency Management. Authorities were evacuating the Canon Park, Seven Hills and Knollwood subdivisions.
In downtown Boulder, all city offices closed Friday afternoon in preparation of rolling power outages caused by the wildfire, a city spokeswoman said. The municipal court and the main branch of the public library were also closed, and classes at the North Boulder Recreation Center were canceled due to health concerns about fire smoke.
The electric utility was cutting power in lines in the burn area for safety reasons and to assist fire crews conducting back-burn operations, the city spokeswoman said.
An estimated 1,700 people live in 800 units within the evacuation boundaries.
"As a precaution and to aid responders dealing with the Dome Fire, we are ordering a mandatory evacuation in some neighborhoods within the city," City Manager Jane S. Brautigam said.
"We are asking that residents follow the directions of emergency crews now so that emergency equipment can be positioned and crews can focus on extinguishing the wildfire. Resident and business cooperation is greatly appreciated as we work to contain this fire," Brautigam said.
CNN iReporter Parker Roe, 34, of Boulder said he could "feel the nervous energy in town" as residents are concerned about how the wildfire threatens their community and homes. When he and his wife stepped out of their house Friday morning, Roe thought "not again" as he smelled smoke and saw flames in the mountain about 2 miles away, he said.
"The first thing that people do when they walk out of a store is look up in the air and shake their head," said Roe, a musician and writer. "We can see the flames on the eastern face of the mountain, which was pretty scary."
Authorities said a plane was making water drops to battle the fire, which began Friday morning. A spotter plane also circled the skies.
CNN's Melanie Whitley contributed to this report.