Continued Risk of Flooding and Mud, Debris Flows from 2017 Wildfires

Posted on October 1, 2019

Sonoma County Recovers

The City of Santa Rosa (City) and County of Sonoma continues to encourage residents living in and around the areas burned by the Sonoma Complex Fires to prepare their property for the rainy season and remain alert for possible threats from intense winter storms. Properties in the areas burned, and downstream of those areas, still have an elevated risk for flash floods, rock falls, debris flows, and mudflows.

The areas affected by the Nuns, Tubbs, and Pocket Fires did not experience any significant debris or mudflows over the last two winters. While these areas have seen substantial improvement in soil and plant growth conditions, the threat of natural hazards from winter storms still exist. The highest danger occurs during intense or prolonged heavy rainfall, but once soils are saturated, floods or mud and debris flows can occur hours or days after the rain has stopped. Property owners in burned areas, and downstream of burned areas, can help prepare themselves and prevent erosion and water quality impacts, by following these steps:

  1. Take Precautions for your Family
    • Check the Post-Fire Hazard Map for an estimate of the risk in your vicinity. Localized or changing conditions may result in a greater threat than displayed on the map.
    • Pack emergency supply bags and identify what you’d want to save in an emergency. Consider the 6 P’s: People and Pets, Important Papers, Prescriptions, Pictures, Personal Computers, and Plastic/Paper money.
    • Create an evacuation plan and include two possible evacuation routes.
    • Prepare your Property
  2. Prepare your Property
    • Use erosion control techniques, such as installing straw wattles and rock bags, and remove excess debris near creeks, storm drains and drainageways on your property.
    • For additional erosion prevention information, visit For questions, if your property is in the City of Santa Rosa, call 707-543-4649. In the unincorporated County, call 707-565-6186.
  3. Remain Alert- Know how you’ll receive alerts:
    • Wireless Emergency Alerts: Always keep your phone on, with the ringer on, to receive alerts from the National Weather Service.
    • SoCoAlert: Sign up to receive emergency notifications at SoCoAlert will be used to send an emergency notification if there is an imminent threat to life or property.
    • In areas with limited cell service, or in areas that may experience power outages, have a battery-powered weather emergency radio on hand to receive critical messages from the National Weather Service.

The City and County are working in close coordination to prevent and monitor flooding. A series of rain and stream flow gauges were installed within and downstream of the burn areas by Sonoma Water as part of an early warning system for flooding. The gauges allow monitoring of streams and rainfall in real-time and offer a glimpse of conditions in the burn areas and downstream of areas that are vulnerable to flooding. Data from the gauges are used by the National Weather Service to develop its hazardous weather advisories, alerts, and warnings. This real-time rainfall and streamflow data is available at

To assist property owners in the burn areas with managing stormwater runoff, the City and County have developed best management practices for the installation of erosion control measures at vacant lots and construction sites. These practices are designed to reduce erosion and the amount of sediment that washes off sites during rain storms – potentially causing pollution in creeks and blockage of drainageways. The County is conducting site visits at locations in the burn areas to ensure erosion control measures are properly installed and maintained.

For more information, visit

Questions: 707-565-3040

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