(CNN) -- A fast-burning wildfire in Northern California's Santa Cruz Mountains grew to 3,100 acres Friday, prompting rescues and evacuations in two counties, officials said.
But firefighters got some help from the weather, as high winds that had fanned the wildfire faded. The winds dropped from around 30 mph to 2 mph.
The fire began before dawn Thursday and has burned at least 12 homes and threatened about 500 homes and 20 businesses, said Chris Morgan of the California Department of Forestry and Fire Protection.
No injuries were reported. Watch flames devouring a forest »
More than 1,700 people have been evacuated, according to the department -- 350 of them mandatory evacuations.
The Santa Cruz Mountains are dotted with multimillion-dollar homes over rugged terrain. iReport.com: Send photos, videos of the fires
Ian McClelland, who lives in a small community overlooking the ocean and the town of Santa Cruz, saw an orange glow above the hills upon awakening Thursday, he told CNN affiliate KSBW-TV in Salinas. He let his two horses go free in hopes it was their best chance for survival.
"There was not an opportunity to do anything," McClelland told KSBW. "There was no opportunity to put them in a trailer. So I just let them loose. They had a good chance that way."
McClelland returned to his home later, only to find the foundation remaining. Two of his 10 dogs died in the fire, he told KSBW.
"I don't think it's hit me yet," McClelland said, his voice trembling.
Rebecca Henson, 45, woke up Thursday to find smoke and ash drifting around her wood cabin in Corralitos, according to KSBW. She said she quickly evacuated with her dog, knowing she might not see her home again.
"That thing's going to go up like a torch -- it's got wood floors, wood ceilings, everything," Henson told KSBW. "There wasn't an official evacuation, but we're mountain folks; and we're pretty used to independent living. So it didn't take too much common sense to realize this thing is close, we've got to go."
Kenneth Kim, 66, watched with binoculars from a ridge to see if his home, near McClelland's, would escape the blaze, KSBW reported. At first, he said he was optimistic, but when the smoke cleared, he could see his house starting to burn, according to the station.
"Oh, it's gone. It's smoldering," Kim told KSBW. "I feel very scared, mad and ... to start all over, I don't know how."
The wildfire was burning in rugged, mountainous terrain in Santa Clara County and moving south into Santa Cruz County, south of the San Francisco Bay Area.
Five planes and 10 helicopters have been used to drop water on the fire since Thursday, including a "Supertanker" -- a jumbo jet modified to battle fires from the air.
More than 500 firefighters and personnel are battling the blaze.
The fire's cause is under investigation.
CNN's Augie Martin contributed to this report.
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