Santa Ana winds will bring dry air and high gusts to Southern California, significantly increasing the threat of fires over the Thanksgiving holiday, the National Weather Service said. More than 3 million residents from the Los Angeles to San Diego area are under fire warnings.

“Those living near fire prone undeveloped areas, like the national forests, should make or review the family plan including what to take and evacuation routes in the event of an evacuation order is issued or a nearby wildfire threatens,” National Weather Service Los Angeles said in a forecast. “This is especially important with unaware visitors during the holiday week.”

The Santa Ana winds, dry coastal gusts that usually affect Southern California, are currently blowing between 40 to 60 mph. Humidity is low — around 2 to 8% — bringing dry conditions to Los Angeles, Santa Monica, Burbank and areas east of San Diego. If a fire begins, officials say the combination of dry weather and fast winds will spread any blaze that starts. 

CAL Fire tweeted Wednesday it has two fire engines and 124 crew members, stationed in Riverside, San Bernardino, San Diego and Los Angeles, ready in case of a fire. 

“Fire prevention begins at home,” Riverside County Fire Chief Bill Weiser said. “During the Thanksgiving holidays, we want everyone to enjoy their time with family and friends safely and responsibly.”

Southern California Edison officials also warned that utilities and power could be shutoff to prevent fires from power lines. Over 151,639 customers were at risk of losing their power during Thanksgiving as of Wednesday morning, including 45,743 in Riverside County, 35,438 in Ventura County and 33,398 in Los Angeles County, CBS Los Angeles reports

The red flag fire weather warnings are expected to continue into Friday, even as pressure and winds weaken through the weekend.