What to Know Santa Ana winds will develop by early Thursday and continue through Saturday

The fire-whipping winds are produced by surface high pressure over the Great Basin squeezing air down through canyons and passes

Fall is historically the worst time of the year for damaging wildfires in California

Dangerous Santa Ana winds are expected to pick up this week as Southern California enters one of the worst times of the year for wildfires.

The winds will develop by early Thursday and continue through Saturday, raising the fire risk across Ventura and Los Angeles counties. Weaker winds are expected in Santa Barbara County.

In inland communities, moderate Santa Ana winds are expected Thursday before they decrease Friday.

"Fire threats are going to be a concern," said NBC4 forecaster Shanna Mendiola.

The fire-whipping winds are produced by surface high pressure over the Great Basin squeezing air down through canyons and passes in Southern California's mountain ranges. They're common in the fall and have a long history of fanning destructive wildfires in the region.

Fall is historically the worst time of the year for damaging wildfires in California. Seven of the state's 10-most destructive wildfires have occurred in October and November.

So far this year, Southern California has not seen the large fires that devastated parts of the state last year, largely due to above-average soil moisture and an active monsoon season that followed a winter of steady rain.

Through September, CALFIRE reported 4,460 wildfires that burned about 40,400 acres. Last year at that time, the agency reported 4,800 fires that burned a staggering 627,600 acres.

California's five-year average for that time period is 324,600 acres.

An onshore flow returns Sunday, bringing cooling to the region.