A wildfire in California threatened up to 12,000 homes on Monday, a day after two fire-fighters were killed when their vehicle was overrun by fast-moving flames and rolled down a mountainside.

An essential communications centre in Los Angeles County and an astronomy centre were also in danger. On the blaze’s north-western front, the two fire-fighters were killed on Sunday on Mount Gleason near the city of Acton.

The blaze was only about 5 per cent contained late on Sunday and had scorched 184 sq km in the Angeles National Forest. Mandatory evacuations were in effect for neighbourhoods in Glendale, Pasadena and other smoke-choked cities and towns north of Los Angeles. At least 18 homes were destroyed in the fire and firefighters expected to find many more, authorities said.

“Our neighbours sent us photos of all the other houses that are lost,” said Beth Halaas, who lost her house in Big Tujunga Canyon, one of the many communities under mandatory evacuation. “We’ve heard as many as 30 houses burned.”

On Mount Wilson, crews cleared brush and sprayed retardant in an attempt to ward off flames approaching the transmitters of more than 20 television stations, many radio stations and cell phone providers, U.S. Forest Service Capt. Mike Dietrich said.

Television stations said if the antennas burn broadcast signals would be affected but satellite and cable transmissions would not be.

Two giant telescopes and several multimillion-dollar university programmes are housed in the century-old Mount Wilson Observatory. The complex of buildings is both a historic landmark and a thriving modern centre for astronomy.

The fire has been growing steadily, doubling in size on Sunday.

A slight dip in temperatures was expected on Monday, but temperatures in the 90s F (30s C) and low humidity would remain the norm.

The fire was the largest of many burning up and down California, including a blaze northeast of Sacramento that destroyed 60 structures, many of them homes in the town of Auburn. The fire had wiped out an entire cul-de-sac, leaving only smouldering ruins, a handful of chimneys and burnt cars.

More In: International | News