Southern California is bracing for an "unprecedented" third Particularly Dangerous Situation warning in a month, as extreme Santa Ana winds increase fire danger.

The National Weather Service issued a "particularly dangerous situation" alert for Los Angeles and Ventura counties as another dangerous wind event is expected this week.

Gusts of up to 70 mph are possible along the coast and valleys, and in the mountains, up to 100 mph, the National Weather Service said. Swaths of Los Angeles County, and most of Ventura County, are at the highest risk.

This is the third PDS warning issued within 14 days in the greater Los Angeles area, which is "unprecedented" for the region, according to the National Weather Service.

A final round of dangerous fire weather is in the forecast for Wednesday in Southern California as the region battles ongoing wildfires. Here's what to know.

Here's a guide to understanding "particularly dangerous situation" red flag warnings, containment, and other terms related to the devastating fires that have left much of the LA area in ruins.

Californians in the greater Los Angeles area have been on edge due to high winds and dry conditions. The Palisades and Eaton fires have killed at least 25 and destroyed thousands of homes.