UPDATE 1-Massive wildfires threaten two California towns

(Updates with firefighting efforts near Santa Barbara, other details)

By Dan Whitcomb

LOS ANGELES, July 3 (Reuters) - California firefighters made a desperate stand as darkness fell on Thursday to save more than 4,000 homes and other structures from a pair of out-of-control wildfires burning about 170 miles (273 km) apart along the California coast.

The most imminent danger was to homes around Goleta, near Santa Barbara, where flames were fast approaching 2,600 homes and transmission lines supplying power to 100,000 people on the central coast.

All told, some 3,000 residences had been evacuated in and around Goleta, a town of about 30,000 people, and officials said the threat to life and property had made it the state's top firefighting priority, despite more than 1,000 other blazes burning across the state.

"The entire sky here in Goleta is black with smoke and we're evacuating several more locations," Cal Fire spokeswoman Karen McKinley said on Thursday evening of the Gap Fire, which broke out on Wednesday afternoon and had charred more than 2,400 acres (971 hectares).

Asked how close the flames were to the nearest homes, she said: "It may be at them right now. This is a critical moment."

Meanwhile, the 64,000-acre (25,900 hectare) Basin Complex Fire raged into the night on Thursday in the foothills above the scenic coastal community of Big Sur, where 1,800 homes and businesses were evacuated and 25 miles (40 kms) of coastal highway shut down.

'ITS GETTING SERIOUS'

Whipped by high winds and burning through drought-ridden wilderness areas, only about 5 percent of the Basin Complex Fire has been contained.

"This is a very active fire. Last night we were seeing 150- to 200-foot flame lengths and generally at night fires do not act like that," Cal Fire spokeswoman Tina Rose said.

"It would not surprise me, unfortunately, if some more homes were destroyed. I hope not. We are trying very hard to protect them. ... It's go time in Big Sur," she said. "There's no messing around. It's getting serious."

Already the Basin Complex Fire had destroyed 20 homes and another 1,777 structures in the area were considered threatened.

Evacuation order was extended to cover the 25 miles of coastline after the National Weather Service issued a red flag warning over higher winds and lower humidity.

Complicating the situation was that the forests have been plagued by disease since the mid-1990s, she said, killing many trees in the area and providing ready fuel.

"There are literally thousands of dead oak trees in the fire area," Rose said. "It's basically firewood."

She said fire crews did not expect to fully contain the Basin Complex Fire for weeks.

California Gov. Arnold Schwarzenegger, who visited the Big Sur area on Wednesday, has ordered National Guard troops to provide ground support.

Schwarzenegger has declared declared a state of emergency in 11 counties in central and Northern California where more than 1,000 fires have been burning for days, blackening more than 425,000 acres (172,000 hectares).