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.

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.

Wildfires fueled by strong Santa Ana winds have devastated Southern California, destroying thousands of homes and causing 27 deaths. The fires, affecting urban areas and the Olympic preparation, are worsened by climate change and urban expansion.

Tree limbs that break off in high winds were often incorrectly pruned, plus how much defensible space is enough for fire safety?