section_path: Background
section_name: Background
paragraph_text: Background
  
  A strong high-pressure system over the Great Basin created a steep northerly pressure gradient across Southern California. The system triggered powerful Santa Ana winds, katabatic winds that can develop when cooler, dense inland air is funneled through mountain passes and canyons toward the warmer coastal regions.
  
  The area had experienced "eight months without any measurable rainfall", and much of the region had fallen into moderate drought conditions. A battalion chief for the California Department of Forestry and Fire Protection (CAL FIRE) told the Los Angeles Times that the conditions were "the perfect recipe for a large wildfire". The National Weather Service (NWS) issued red flag warnings on the morning of January 6, effective through Thursday evening, for multiple regions, including the Malibu coast, Santa Monica Mountains Recreational Area, and the San Gabriel, San Fernando, and Santa Clarita valleys.
  
  NWS predicted a "life-threatening" windstorm and Santa Ana wind gusts were forecast to reach speeds of 60–80 miles per hour (97–129 km/h), with some gusts anticipated to reach 90 mph (140 km/h) in mountainous areas. Residents were urged to "use extreme caution with anything that can spark a wildfire" and those near forests to be prepared to evacuate. The danger posed by the windstorm and weather patterns led Caltrans to close several roads, including Topanga Canyon Boulevard between Mulholland Drive and Pacific Coast Highway.
  
  As is common in red flag warnings, CAL FIRE pre-positioned firefighting assets across Southern California. The Los Angeles Department of Water and Power topped off all three of its 1-million-gallon water tanks in the area affected by the red flag warning, a precaution against the loss of water pressure during the sudden demands of firefighting, especially at higher altitudes. Despite these efforts, 20% of fire hydrants eventually ran out of water in the more elevated parts of Pacific Palisades.