If you would like to attend our webinar:
El Niño Webinar
Oct 15, 2026
10:30 a.m.
What is El Niño?
El Niño is a naturally occurring climate pattern that begins when surface waters in the central and eastern tropical Pacific Ocean become warmer than usual. These changes can influence weather patterns around the world and, during some El Niño winters, contribute to wetter and stormier conditions in California.
El Niño does not guarantee that a particular community will experience heavy rain or flooding. However, preparing early can help you and your household respond when severe weather does occur.
Listos California
Sign up for emergency alerts.
Ready.gov
Plan ahead for disasters.
Cal MyHazards
Discover hazards in your area.
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What Does El Niño Mean for Our Community?
El Niño can contribute to wetter and stormier conditions in California, but every season is different. When powerful storms reach our region, impacts can vary significantly from neighborhood to neighborhood.
Residents should be prepared for:
- Flash Flooding: Heavy rainfall can overwhelm streets, storm drains and other drainage systems, causing rapid flooding in low-lying areas and neighborhoods.
- Mudslides and Debris Flows: Hillsides and areas recently affected by wildfires can be especially vulnerable to mud, rocks and debris moving downhill during intense rainfall.
- Power Outages: Strong winds, saturated soil and falling trees or branches can damage power lines and interrupt electrical service.
- Road Closures and Travel Disruptions: Flooded streets, debris, fallen trees and damaged infrastructure can affect freeways, local roads and public transportation.
- Coastal Hazards: Storms can bring large waves, dangerous surf, coastal flooding and erosion.
- Impacts to Homes and Property: Roof leaks, fallen trees, water intrusion and localized flooding can cause significant property damage, even outside designated flood zones.
Be Prepared Before the Storm
Preparing before storms arrive can help protect your household, property and community.
A little preparation can make a major difference when severe weather arrives. Know whether your home is in an area vulnerable to flooding, keep emergency supplies available, make a household emergency plan and sign up for local emergency alerts.
Know Your Alerts
During severe weather and other emergencies, local authorities may use several systems to warn you about dangerous conditions. Knowing where those alerts come from — and which ones require you to sign up — can help you get critical information when you need it.
San Mateo County Emergency Alerts | SMC Alert
SMC Alert is San Mateo County’s primary alert and warning system to contact you during emergencies, such as fire, weather, utility accidents, earthquakes, or flooding.
Prepare Your Coastal Property for El Niño | California Coastal Commission
If you live along California's coast, now is a good time to prepare your property for strong storms, heavy rainfall, large waves, flooding, and erosion.
Don't Rely on Just One Source
During a major storm or emergency, information may come from multiple agencies. Keep Wireless Emergency Alerts enabled on your phone, sign up for your local notification system and follow instructions from local emergency management and public safety agencies.
Tip: If you have family members, older adults or neighbors who may need assistance during an emergency, help them check their phones and sign up for local alerts too.
Stay Informed
Weather conditions can change quickly. During a storm, rely on official weather forecasts, emergency alerts and instructions from local public safety agencies.
Use the resources below to find current weather information, road conditions, emergency services and local alerts:
These resources provide supplemental information and tools to support preparedness. They do not replace official government alerts, National Weather Service warnings or instructions from local public safety agencies. Always follow official evacuation orders and emergency instructions.
Make a Family Plan
- Build a personal support network of at least two or three trusted neighbors, friends, or caregivers who can check in, help with evacuation, or provide support if needed.
- Develop a family plan before any stormy weather occurs. Involve the whole family when making the plan to ensure everyone knows what to do.
- Designate an emergency meeting location outside the hazard area. Have important phone numbers on hand to quickly contact in case of emergency.
- Identify several different routes to leave your home in case one or more are blocked. Be aware of any creeks, drainages, or other areas that could flood or become hazardous during rainy weather.
- Build an emergency kit by preparing 72 hours of water, non-perishable food, and essential medications. Keep supplies at home and in your car to support you and your family in the event of an emergency (power outage, shelter in place, evacuation, etc.). Learn about emergency kits in Ready.gov.
Check your Insurance Coverage
- Review your insurance coverage. Homeowners, renters, and commercial insurance policies typically exclude damage caused by flooding, mudslides, debris flows, and other similar disasters unless they are directly or indirectly caused by a recent wildfire or another covered peril. However, policies may provide coverage for certain water damage caused by wind-driven rain. Damage caused by fallen trees is generally covered under all standard homeowner policies. Renters should review their renters’ insurance to understand coverage for their personal belongings, which generally are not covered by a landlord’s insurance policy. Consumers should contact their insurance company or agent to understand their coverage before severe weather arrives.
- Consider flood insurance. The National Flood Insurance Program provides the majority of flood insurance coverage written in California, and private flood insurance is also available. Flood insurance generally takes effect 30 days after purchase, except in the case of a home purchase where flood insurance is required by the lender. Consumers should plan rather than wait until a storm is approaching.
- Review your auto coverage. Comprehensive auto insurance can provide coverage for vehicles damaged by flooding, fallen trees, and other storm-related events. Check your auto insurance declaration page to see if this optional coverage is included in your policy or contact your insurance company or agent.
Important Safety Information
For an emergency requiring immediate police, fire or medical assistance, call 911.
During a natural disaster or severe weather event, always follow official government alerts, evacuation orders and instructions from local emergency management and public safety agencies. Consult the National Weather Service for official weather forecasts and warnings. Do not delay emergency action while seeking information on this page.
DISCLAIMER: The El Niño Preparedness Hub is provided for general educational and informational purposes only. It is not an emergency notification system and does not replace official instructions, individualized professional advice or an assessment of your household’s needs. Consider your location, health, accessibility needs, property conditions and other personal circumstances when planning, and consult appropriate professionals as needed.
