Summary (tl;dr)

A tornado warning was briefly issued for several communities in Los Angeles County on December 24, 2025, amidst a powerful atmospheric river storm bringing heavy rain, strong winds, and flooding to California.

Essential Background

California, particularly the Southern California region, is currently experiencing a "very dangerous" atmospheric river storm, often referred to as a "Pineapple Express" event, which draws significant moisture from the Pacific Ocean. While less common than in the central and southeastern United States, tornadoes do occur in California, typically being weak and associated with winter storms. Los Angeles County has historically recorded the highest number of tornadoes in the state.

The Full Story

On Wednesday, December 24, 2025, the National Weather Service (NWS) issued a tornado warning for parts of east-central Los Angeles County, including Alhambra, Monterey Park, Rosemead, Pasadena, San Gabriel, El Monte, and Temple City. The warning, in effect until 10:45 AM PST, was prompted by a severe thunderstorm capable of producing a tornado, moving northeast with wind gusts up to 60 mph. The tornado threat diminished shortly after, leading to the cancellation of the tornado warning; however, severe thunderstorm warnings, indicating damaging winds, remained in effect for the affected areas. This event occurred as the first wave of a massive atmospheric river storm dumped heavy rain across the Southland, causing widespread urban flooding, rockslides, and raising concerns about debris flows in recent burn areas, leading to evacuation warnings and orders in parts of Los Angeles and Orange Counties. Earlier, severe thunderstorm warnings for Los Angeles and Ventura Counties mentioned wind gusts up to 70 mph and advised residents to remain alert for possible tornadoes.

Why It Matters

The unexpected issuance of a tornado warning in a densely populated area like Los Angeles County, where such events are rare, has spurred significant public concern and increased searches for safety information. The broader severe weather system, characterized by heavy rainfall and powerful winds, poses substantial risks of widespread urban and flash flooding, mudslides, debris flows, and downed trees and power lines, severely disrupting holiday travel and threatening life and property across the state. Authorities have urged residents to take warnings seriously, reconsider travel plans, and prepare for potentially "life-threatening" conditions throughout the holiday period.

Geographic Location

• Alhambra, Los Angeles County, California, United States (tornado warning issued)
• Monterey Park, Los Angeles County, California, United States (tornado warning issued)
• Rosemead, Los Angeles County, California, United States (tornado warning issued)
• Pasadena, Los Angeles County, California, United States (tornado warning issued, severe thunderstorm warning remained)
• San Gabriel, Los Angeles County, California, United States (tornado warning issued)
• El Monte, Los Angeles County, California, United States (tornado warning issued)
• Temple City, Los Angeles County, California, United States (tornado warning issued)
• Los Angeles County, California, United States (severe thunderstorm warning with potential for tornadoes, urban flooding, rockslides, debris flows)
• Ventura County, California, United States (severe thunderstorm warning with potential for tornadoes, heavy rain)