Prepare for Flooding

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Here are some preparation tips specifically for flooding


  • Register for San Mateo County Alert to receive emergency alerts via text, phone
  • Prepare emergency supplies to last 72 hours. Non-perishable food, water, batteries, flashlights, a manual can opener, and a battery-operated radio should be kept available disaster supply guide.
  • To protect from flood water - If your area is prone to flooding fill up sand bags protect your property at the City fill in station. 110 Higgins Canyon Road Half Moon Bay CA 94019. 
  • Prepare an emergency/evacuation plan Often the best option is to shelter in place at home and to stay off the roads until the situation is safe. 
  • Help keep storm drains in your neighborhood clear. This will help  prevent backups and localized flooding in your neighborhood. Call Half Moon Bay Public Works Maintenance at 650.726.7177 for significant blocking. (after 5pm, call the Sheriff's dispatch at 650.726.8286).
  • Know if your property is in a flood zone; consider flood insurance - click here to view FEMA's Flood Insurance Rate Maps (FIRM) for Half Moon Bay.  Regular homeowner's insurance policies usually don't cover flood damage, so you may want to consider purchasing flood insurance to protect your home and its contents. 
  • Check the National Weather Service Half Moon Bay Forecast Page for weather updates.


  • Make sure your family and pets are safe - if there is time, move valuable household possessions off the floor.
  • Place sandbags appropriately as necessary - If a flood is imminent, property can be protected by sandbagging areas subject to the entry of water into living spaces. The Half Moon Bay "self-help" sandbag distribution center (bags and sand for you to fill) is at the Historic Train Depot below Johnston House 110 Higgins Canyon Road (for Half Moon Bay residents only).
  • Check for SMCAlert Messages - if you haven't already done so, sign up with SMCAlert.
  • Avoid flood waters- Be cautious. Flood waters rise rapidly, so be prepared to evacuate before flood waters reach your property. If dangerous flooding conditions are imminent, avoid driving a vehicle if possible. 
    • Six inches of water will reach the bottom of most passenger cars and will cause the loss of control or stalling and a foot of water will float most vehicles. 
    • Two feet of rushing water can carry away most vehicles, including trucks and SUVs. If you are in a stalled car, abandon it as quickly as possible. Flood waters can rise quickly and sweep a car away. 
    • Do not attempt to move a stalled vehicle, or drive or wade through deep pockets of water. 
    • If you are caught by suddenly rising waters, move to the second floor, or the roof if necessary. Wait for help. Do not swim for safety. Rescue teams will be looking for you. 
  • Avoid low-lying areas - If outside, look for higher ground. Seek shelter in the highest areas possible. Unstable banks or berms should be avoided. 
  • Disable utilities - If your property is in imminent danger of flooding, you may need to shut off your gas and electricity for safety. Visit PG&E online for information about how to do this. If you smell natural gas, see downed power lines, or suspect another power-related emergency situation, call 9-1-1 and then call PG&E at 1-800-743-5000. Do not touch any electrical equipment unless it is in a dry area and you are standing on a piece of dry wood while wearing rubber gloves and rubber soled boots or shoes.
  • Be ready to evacuate if directed by emergency personnel - the City/County may order optional or mandatory evacuations depending upon conditions. If evacuations are called for, it is imperative that you follow instructions of emergency personnel in the time frame noted.