SAN JOSE (CBS SF) — A slow-moving wildfire fueled by tinder-dry brush grew to more than five acres early Thursday as it burned in the steep, rugged terrain of the south San Jose hills.

San Jose Fire Battalion Chief Robert Culbertson said his agency received several calls reporting the blaze around 3 a.m.

The fire was a mile and a half deep inside private property where there was no public access not far from some high-voltage PG&E transmission lines. Crews rushed to the hills but were immediately challenged by the remoteness of the terrain.

“It’s very difficult access,” he told KPIX 5. “It took us about an hour to first find the fire through a small network of cattle roads. It’s really difficult terrain. Some of the access roads actually had trees across them.”

Darkness meant there would be no help from helicopters or tankers dropping water and retardant until after dawn.

Fortunately, wind conditions were relatively calm as the blaze was being fueled by brush that had been dried out by several days of record heat.

The fire was slow moving and had grown to just over five acres at sunrise.

Cal Fire brought in bulldozers and nearly 100 firefighters to mount an aggressive ground attack.

They kept the fire to 30 acres. It had the potential to spread to 100 acres.

The possible point of origin was marked off by some red tape. On the ground there’s not much to see, but up above, a balloon made of some kind of shiny, metallic, foil-like material was visible.

Crackling was audible as the wind blew the balloon into contact with the other lines.

“How did this fire start? Currently we have an area of origin, so we will have our investigator hopefully in the next half hour,” said George Huang with Cal Fire. “They will do a full investigation to determine the cause.”

Culbertson said no structures were threatened.

An aggressive attack early helped limit the spread of the fire.

“Given the time in the middle of the night, we had to send a lot of resources to put out the fire and prepare ourselves for what could come today with additional fires within the county,” said Huang.

As for the fire season itself, due to climate change, there really is no start or end anymore.

“As you’ve seen today, in the last few days, from Contra Costa County, all the way to Santa Clara County, we’ve known this is going to be another bad fire season,” said Huang. “So we want to make sure that any property owners do their due diligence with defensible space. We’re here but at the same time, fuels are very dry. And if everybody does their part, it allows us to do our part.”

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