MORGAN HILL, Calif. — A grass fire along a Northern California highway spread to parched trees, and flying embers landed on nearby homes, setting at least eight homes on fire, authorities said.

The fire started on vegetation and quickly spread to a row of Eucalyptus trees lining Highway 101 in Petaluma, California, Petaluma fire Battalion Chief Jeff Holden said.

The flames apparently damaged gas service valves on multiple homes, and “flames shot like a torch in the attic,” Holden told the Santa Rosa Press Democrat newspaper.

At least two homes were gutted, but authorities had yet to assess the extent of the damage on the other six homes.

A heat wave baking drought-stricken California worsened a wildfire Tuesday that burned two buildings and forced people from their homes in remote communities along the Santa Cruz Mountains.

One remote area where the fire burned is 30 minutes up a winding dirt road. Another is dotted with large-scale marijuana growing operations. A main route along the ridgetop is not accessible, even to firefighters, because of downed utility lines.

Flames lit up the mountainside above a roller coaster at Santa Cruz Beach Boardwalk, and a residence was reduced to rubble, though its hot tub still stood. The fire consumed a large home sitting on a hilltop plot and poured out thick, black smoke, while another house sat unscathed below.

“This fire is a good reminder that even though we are approaching October, this time of year is historically when we experience the largest and most damaging wildfires,” Cal Fire spokesman Daniel Berlant said.