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. Parts of L.A. County, and most of Ventura County, are at highest risk.

With the PDS warning, officials said Monday that residents should be prepared to leave immediately as the critical fire danger weather ramps up.

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.

The Los Angeles region, still reeling from this month’s firestorm, is under a red-flag warning from noon Monday through Tuesday morning.

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.

The National Weather Service issued its highest fire weather alert level for portions of the Los Angeles area for Monday into Tuesday morning, as powerful Santa Ana winds return. Threat level: The "Particularly Dangerous Situation" Red Flag Warning indicates any fires that ignite could quickly grow out of control.