Santa Ana Winds Sweep Brush Fire Over 125 Acres : Blaze: Seasonal conditions fuel flames sparked by downed power line. A mini-mall and preschool are evacuated but no buildings are damaged.

A wind-whipped brush fire swept across 125 acres of canyon land in the Santa Clarita Valley on Wednesday, threatening homes, commercial structures and a preschool before being brought under control.

Fire officials said the blaze apparently started about 11:15 a.m. when dry Santa Ana winds gusting up to 20 m.p.h. downed a power line near Bouquet Canyon Road and Shadow Valley Lane.

Spreading rapidly south, the flames reached within a few yards of homes on Nicholas Circle Drive before 150 Los Angeles County firefighters controlled the blaze with backfires about 1:45 p.m.

A mini-mall and preschool on Bouqet Canyon Road were evacuated briefly, but residents were allowed to remain in their homes.

Dan Bowman, a meteorologist with WeatherData Inc., which provides forecasts for The Times, said Wednesday’s warm, breezy weather resulted from a situation that is familiar at this time of year: a large high-pressure system over northern Nevada and a low-pressure system off the southern tip of Baja California.

Winds from the high-pressure system flow toward the lower pressure off the coast, warming and drying out by compression as they spill down the coastal canyons surrounding the Los Angeles Basin.

The high temperature at the Los Angeles Civic Center on Wednesday was a balmy 75 degrees, and forecasters said today’s top reading should be 82. The relative humidity Wednesday was well below normal, ranging from a maximum of 56% to a low of 12%.

Bowman said the winds should diminish this morning as the high-pressure system continues to move east, but high temperatures in the upper 70s and low 80s are expected to continue into the weekend.