(CNN) -- Residents in Boulder, Colorado, were allowed to return to their homes Saturday after an area wildfire forced an estimated 1,700 people to evacuate.
The Dome Fire had burned 152 acres as of Saturday midday, and was about 70 percent contained, Boulder County Sheriff's Office Cmdr. Rick Brough told reporters. All evacuation areas were opened up Saturday morning, he added.
"We basically had no growth overnight," said Brough.
Several residential subdivisions on the west side of the city were evacuated Friday as the wildfire spread in Boulder Canyon. An estimated 1,700 people live within the borders of the evacuation area.
The cause of the fire is still under investigation, though Boulder County Sheriff Joe Pelle said it was likely sparked by human activity.
"There weren't really any weather events," he said.
Pelle added that he expects the 30 percent that is not contained to be the hardest to bring under control as the fire burns along steep, rocky ground that complicates efforts to reach it.
When pressed by reporters as to when he think the fire will be 100 percent out, Pelle declined to pinpoint a day.
But, he added: "If we don't have a wind event, or some major issue like that come up, I think we're going to be in pretty good shape."
Energy officials were expected to tour the region to assess damage and restore power as some utility lines remained down in the burn area Saturday.
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 smoke from the blaze.