The fire threatened structures in the area of Old Page Mill and Page Mill roads and prompted a voluntary evacuation of homes, but no structures were damaged and no injuries to residents or firefighters were reported.
Police believe the fire was most likely caused by human activity, and are investigating whether it was started accidentally or intentionally. Investigators found that a water generator, which they originally thought caused the fire, was unplugged.
Firefighters from units as far south as Gilroy and aerial support from the California Department of Forestry and Fire Protection (Cal Fire) responded to the conflagration, which broke out at around 4 p.m. Cal Fire first received word at 4:13 p.m.
Smoke from the fire could be seen from many miles away. In Mountain View, great plumes of smoke blotted out much of the sky to the northwest.
The fire was fully contained by 7:30 p.m. Monday evening, according to Palo Alto police and fire communication manager Charlie Cullen.
Hao Thai, a science and engineering associate at Stanford University, was inside the university's Wilcox Solar Observatory on Reservoir Road when the wind started blowing the fire south towards the observatory. He noticed smoke dimming the sunlight as he took magnetic field measurements of the sun.
Then he began to hear sirens, and firefighters arrived. The flames hit the 15-foot fire break surrounding his building and went around, he said. Firefighters told Thai to "hunker down" and stay inside.
"They knew what they were doing, so I didn't worry too much," he said, while adding that it was nonetheless a scary experience.
On Tuesday, joggers and hikers streamed to Dish trailhead at Stanford Avenue and Junipero Serra, hopeful of taking a morning walk and viewing the fire damage. However, they were turned away. An officer from the Stanford Department of Public Safety said that hot spots could still ignite up to 48 hours following a blaze.
Firefighters remained in the area, but all nearby streets were open.
The incident area is called the Junipero Serra/Frenchman's area and includes the foothills north of Page Mill Road, east of Highway 280 and west of Junipero Serra. The blaze consumed coyote brush and oak trees, officials said.
California has declared fire season early this year, according to Palo Alto Fire Department spokesperson Barbara Cimino.
"This is going to be a tough fire season for all of California," she said.