SOUTHLAND – (INT) – As summer winds down, seasonal changes will become more apparent.

September marks the official start of the Santa Ana wind season across Southern California.

Although there is only one day on average for a Santa Ana wind event in September. The number of Santa Ana Days increases considerably in October (6) and November (9).

Colder continental polar air moves into the Great Basin in Utah and Nevada with increasing frequency, which is the governing mechanism for the formation of Santa Ana winds.

A Santa Ana wind day in Southern California is distinctly different from the light offshore winds which normally occur during the overnight and early morning hours of the day. The humidity plunges frequently into single digits dramatically raising the wildfire threat. Moisture content in the native vegetation is reaching its lowest level of the year.

Winds reach their strongest usually below mountain passes and canyons exceeding hurricane force.

The Santa Ana wind season can persist until spring.

Story Date: September 26, 2017