How to stay safe if mudslides and debris flows hit

A debris flow Southern California’s Montecito community in 2018.
Mountain residents’ usual routes could be blocked during a debris flow evacuation, so alternatives are necessary.

As the first rains since mid-November fall, it’s not a bad time to run down the precautionary measures for staying safe from mudslides and debris flows in the Santa Cruz Mountains this winter.


After the devastation wreaked by the CZU fire, the winter rainy season will bring an unprecedented risk of debris flows and mudslides. Residents in and below the burn area could be in danger.

Santa Cruz County officials are urging residents in evacuation zones to fill out an emergency contact form before Dec. 16. You can fill that form out here.

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Among the most important things to know about debris flows? Once you hear one — it sounds like a freight train — it’s too late. Even if you manage to survive, emergency crews won’t always be able to get in to rescue people once the flow has started, so paying attention to evacuation orders is key.

Here’s what else you need to know to keep you safe:


Know your zone

The county has divided the areas at risk of debris flows into zones, which will determine evacuation status. You can check your address on this map to find your zone and risk level.


Stay informed

Sign up for emergency alerts, and consider a battery-operated radio. Sign up here for Santa Cruz Reverse 9-1-1 CodeRed to receive evacuation warnings and orders. Consider attending the county’s next virtual town hall on debris flow, or watch a recording of one of the earlier events. Here are links to view previous town halls for District 5 or District 3.


Make a plan, pack go-bags

Two men look at a map
(via Pixabay)

Know your evacuation route and destination where you will shelter. Plan alternative routes to your shelter site in case roads are blocked.

Pack two emergency kits, one quickly accessible in your house and one in your car. This requires extra care during the covid pandemic: be sure to include face masks in your evacuation go-bag. has some insight into what you should pack in your emergency kit. They suggest storing your things in airtight plastic bags and to put your entire disaster supplies kit in one or two easy-to-carry plastic bins or duffel bags. Here’s what to pack:

  • Water (one gallon per person per day for at least three days, for drinking and sanitation)
  • Food (at least a three-day supply of non-perishables)
  • Battery-powered or hand crank radio and a NOAA Weather Radio with tone alert
  • Flashlight
  • First aid kit
  • Extra batteries
  • Whistle (to signal for help)
  • Dust mask (to help filter contaminated air)
  • Plastic sheeting and duct tape (to shelter in place)
  • Moist towelettes, garbage bags and plastic ties (for personal sanitation)
  • Wrench or pliers (to turn off utilities)
  • Manual can opener (for food)
  • Local maps
  • Cell phone with chargers and a backup battery
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Register for the compelling Kraw Lecture featuring Nobel Leureate Carol W. Greider, who will discuss telomeres, the...

Depending on your needs, you may also consider packing these additional things in your go-bags:

  • Prescription medications
  • Non-prescription medications such as pain relievers, anti-diarrhea medication, antacids or laxatives
  • Prescription eyeglasses and contact lens solution
  • Infant formula, bottles, diapers, wipes and diaper rash cream
  • Pet food and extra water for your pet
  • Cash or traveler’s checks
  • Important family documents such as copies of insurance policies, identification and bank account records saved electronically or in a waterproof, portable container
  • Sleeping bag or warm blanket for each person
  • Complete change of clothing appropriate for your climate and sturdy shoes
  • Fire extinguisher
  • Matches in a waterproof container
  • Feminine supplies and personal hygiene items
  • Mess kits, paper cups, plates, paper towels and plastic utensils
  • Paper and pencil
  • Books, games, puzzles or other activities for children

Leave when you get an evacuation order

Once you can hear a debris flow — it sounds like a freight train — it’s too late. Even if you manage to survive, emergency crews won’t always be able to get in to rescue people once the flow has started.

Debris flows are dangerous: the Montecito debris flows killed more people than the massive Thomas fire that preceded it. Debris flows can hit places they haven’t been before and can return bigger or smaller than where they have been before, so don’t rely on historical experiences as they don’t necessarily inform the future.

drops of water on a fern leaf
Intense rain can trigger debris flows. If you think you’re in danger, don’t wait to get a warning.


Evacuate if you think there’s any danger

Don’t wait to hear a warning if you think you’re at risk, especially if there’s been serious rainfall. This doesn’t mean you need to leave every time it rains though. The real danger is intense rain: about half an inch an hour, like being in a thunderstorm, according to USGS disaster scientist Suzanne Perry.


Wait to return

The county is only evaluating the risk and issuing evacuation orders of inhabited areas. If they don’t think anyone is living there, but you’re occupying it, you may not get the warnings you need. Additionally, the risk of debris flow near a home in the burn area may be serious and need remediation, so don’t move back in unless the site has been inspected by a geologist.

people eating a picnic beneath a tent next to a car
Don’t occupy burned areas unless the site has been inspected by a geologist.


If you have no choice but to shelter in place...

a black and white photo of people standing on a roof
If you don’t have time to evacuate in the case of a debris flow, find the highest ground that you can get to very quickly.
(Nick Amoscato/Creative commons.)

Get to the highest ground you can, but stay indoors—if your house has an attic or second story that’s probably safest. Listen for unusual sounds such as cracking, breaking, or roaring, and watch for mud and rushing water.

Take action
  • Education
    Fill out emergency contact information
    Santa Cruz County officials urged residents in the evacuation zones to complete an emergency contact form by Dec. 16. The survey asks residents for contact information and to identify specific needs should any debris flow event occur in or near the CZU Lightning Fire burn scar. The survey includes a series of questions, and residents need only answer questions relevant to their situation.
  • General Announcement
    Sign up for CodeRED alerts
    Santa Cruz Regional 9-1-1 uses the CodeRED community notification system to send important messages to residents, businesses, and visitors within Santa Cruz and San Benito Counties in the event of emergency situations or critical community alerts.