It feels a bit like deja vu but Southern California is stuck in a weather pattern that has consistently brought the threat of powerful Santa Ana winds and fire danger.

Santa Ana winds occur when air flows west from a region of high pressure over the dry Great Basin to lower pressure off the California coast, According to Accuweather. As that cool interior air flows over and through mountain passes, it accelerates, sinks and compresses.

Jon Keeley, a research ecologist in California with the U.S. Geological Survey and adjunct professor at UCLA, explains what causes extreme winds like this in Southern California, and why they create such a dangerous fire risk.

The three areas impacted by the raging wildfires have one thing in common: They sit at the edges of mountain regions the Santa Ana winds whip through.

Yet another Santa Ana wind event is set to descend upon the Los Angeles area to begin the week, leading weather officials to issue a Fire Weather Watch. According to NWS, “moderate to locally strong” Santa Ana winds are expected to develop Monday and last through at least Tuesday.

A strong and dry Santa Ana event with extreme fire weather conditions is increasingly likely,” the NWS said in a statement. “This event may be considerably stronger for many areas than the event that we experienced this past Monday through Wednesday.