SAN CLEMENTE, CALIF., NOV. 7 -- A wind-whipped brush fire was raging across the sprawling Camp Pendleton Marine Corps base today, choking off the main coastal artery between San Diego and Los Angeles and stalling thousands of frustrated morning motorists in San Clemente.

Passenger train service was halted, 20 miles of freeway was closed to morning rush-hour motorists, a nuclear plant alert was triggered and up to 300 residents were temporarily evacuated, authorities said.

No injuries were reported and no structures threatened by the blaze, which started at 8 p.m. PST Tuesday and crisscrossed the busy freeway just south of San Clemente, burning between 1,500 and 2,000 acres of grass and brush in its path.

The fire swept through the popular San Onofre state beach park overnight but skirted around the nearby nuclear power plant. The fire was enough to spook utility officials, who declared a low-level emergency at 12:45 a.m. when flames jumped the freeway and came within quarter of a mile of the coastal plant.

Plant operations were not jeopardized, but smoke in the power transmission lines resulted in flickering lights in San Diego and Orange counties, said David Barron, spokesman for Southern California Edison.