Owners of properties in areas burned during the devastating October wildfires in the North Bay are being warned about the risk of floods and slides from significant rain storms before vegetation regrows to hold the soil.
The county of Sonoma and city of Santa Rosa on Dec. 26 released an interactive online map (SonomaCountyRecovers.org/rain-ready) showing which parts of the fire areas in Sonoma, Napa, Mendocino, Lake and Solano county are at low, medium or high risk for flash floods and slides of mud and debris. Those governments also are mailing notices to property owners in medium- and high-risk areas and putting up bilingual warning signs on roads leading to the riskiest areas.
Wildfires dramatically alter the terrain and soil conditions and leave the ground unable to absorb water, creating ideal conditions for flash-flooding and mudflows, according to county officials. The National Weather Service expects flash flooding and mudflows to become more likely during periods of intense rainfall, or more than a half-inch an hour.
“A critical part of our fire recovery efforts is continuing to protect the lives and property of those in the areas where the fires burned,” said Shirlee Zane, chairwoman of the Sonoma County Board of Supervisors. “We’re asking people to remain alert, be prepared and protect themselves from the increased risks from flooding after the fires.”
Officials in Sonoma and Napa are working collaboratively on numerous fire-recovery fronts, including efforts to protect the watershed and communicate with residents in the burn areas about the importance of signing up for alerts and remaining vigilant about weather conditions
“Our community continues to be strong and resilient as we recover from this disaster,” said Santa Rosa Mayor Chris Coursey. “As we approach the rainy season, we want everyone to be aware of the increased risks that heavy rains bring, both in the fire burn areas and downstream of those areas. The impacts of this fire are going to be with us for a very long time and being prepared for any emergency is critically important.”
The postcards to property owners include brief descriptions of how to be prepared for flash floods and mudflows, and how to stay informed about potential emergency events. Residents in locations in and around the burn areas are advised to keep their cell phones turned on at all times, and to have their notifications switched on in order to receive emergency warnings from the National Weather Service (weather.gov/alerts) and the county’s SoCoAlert system (SoCoAlert.com).
In areas where there is limited cell service, or if a power outage occurs, emergency warnings from the National Weather Service will be announced on the weather band of emergency radios, which rely on batteries.
Residents are encouraged to have an evacuation plan in place and make sure all family members are familiar with it.
Risks from heavy rains in burned areas
Flash floods: A rapid flooding of a low-lying area in less than six hours, which can be caused by intense rainfall. Flash floods are known to roll boulders, tear out trees and destroy buildings and bridges.
Mudflows: Rivers of liquid and flowing mud on the surface of normally dry land, often caused by a combination of vegetation loss and subsequent heavy rains. They can cause significant damage.
Debris flows: A moving mass of mud, sand, soil, rock and water. They can travel very quickly, and can be very powerful and destructive.
Source: County of Sonoma
More business coverage of the North Bay fires and recovery: nbbj.news/2017fires