What is El Niño?
El Niño Southern Oscillation (ENSO) is a naturally occurring, periodical climate change caused by variations in sea surface temperatures over the tropical eastern Pacific Ocean. The Southern Oscillation is a see-saw shift in surface air pressure between the eastern and western halves of the Pacific. When pressure rises in the east, it falls in the west and vice versa. El Niño is characterized by unusually warm temperatures and La Niña by unusually cool temperatures. The ENSO cycle, both El Niño and La Niña, causes global changes of both temperatures and rainfall.
Learn more about El Niño
- California Department of Fish and Wildlife - El Niño Information
- National Oceanic and Atmospheric Administration - El Niño Portal
- National Weather Service - El Niño, La Niña, and ENSO
Be Prepared
- Sign up for Dept. of Emergency Management emergency alerts
- Report sewer, flooding, power and tree issues to 311
- Receive free sandbags from San Francisco Public Works
- SF72 is San Francisco’s hub for emergency preparedness