Local Hazards

COVID-19


COVID-19 information for the City of Healdsburg can be found here. However, the main resource on COVID-19 in Sonoma County is  www.socoemergency.org.

Drought

A drought is a long-term water shortage caused by an extended period with little to no precipitation that can lead to a decline in available water supplies. Drought vulnerability is primarily measured by its potential impact to sectors of the city’s economy and natural resources. Healdsburg is known as a wine and culinary epicenter. Fortunately, Healdsburg’s economy is relatively balanced and does not depend on tourism to support its economy. Over 57 percent of jobs are not related to wineries. However, the County watershed is currently experiencing what may become the driest period ever recorded. Social impacts mainly involve public safety, health, conflicts between water users, reduced quality of life, and inequities in the distribution of impacts and disaster relief. Potential impacts of a drought include the following:

  • Droughts may cause increases in water rates or additional restrictions on water use
  • Significantly harm agricultural operations
  • Human health risk with severe droughts
  • Increased flooding due to soil hardening
  • Increased risk of wildfire due to wildland vegetation drying out
  • Click here to learn more about current drought information.

Earthquake

Earthquakes are caused by the movement of large pieces of the earth’s crust, called tectonic plates. As the tectonic plates move against each other, they can become stuck together, causing stress between the plates to build up until it eventually overcomes the friction holding them together. When this happens, the stress is released and the plates suddenly slip past each other, creating the shaking that is called an earthquake. Healdsburg is not located within an Alquist-Priolo Earthquake Fault Zone. However, the city is in a seismically active region, and all of Healdsburg is at risk of one or more seismic hazards. All of Healdsburg, including all critical facilities, residential building units, and population, fall within areas with the potential for either a violent or extreme level of ground shaking.

Earthquakes pose numerous risks to critical facilities and infrastructure. Risks, or the harm or losses, that are likely to result from exposure to earthquakes and liquefaction include:

  • Fire from broken gas lines and power lines 
  • Flooding from broken dams 
  • Casualties (fatalities and injuries) from falling debris or secondary hazards 
  • Utility outages
  • Economic losses for repair and replacement of critical facilities, roads, buildings, etc. 
  • Indirect economic losses, such as income lost during the downtime that results from damage to private property or public infrastructure 
  • Roads or railroads that are blocked or damaged can prevent access throughout the area and can isolate residents and emergency service providers needing to reach vulnerable populations or to make repair.

Fault ParametersFaults

Flood

Flooding is a temporary overflow of water onto land that is normally dry. Floods are the most common natural disaster in the United States. Floods may result from rain, snow, coastal storms, storm surges and overflows of dams and other water systems. They can develop slowly or quickly, and flash floods can come without warning. Floods can cause outages, disrupt transportation, damage buildings and create landslides.

What to do Before a Flood:

  • Know your risks for a flood. In Healdsburg flooding occurs on a semi-regular basis, both within the FEMA-identified floodplains and in other localized areas. Per an exposure analysis completed for the City’s LHMP, 20 percent of the city’s critical facilities, about 8 percent of residential structures, and about 9 percent of the city’s population are in a 1% annual chance or 0.2% annual chance flood zone. The Russian River and Foss Creek are the dominant flooding hazards for Healdsburg, with Foss Creek causing most of the flooding in the city.
  • Purchase or renew a flood insurance policy. Homeowner’s insurance policies do not cover flooding. It typically takes up to 30 days for a policy to go into effect so the time to buy is well before a disaster. Get flood coverage under the National Flood Insurance Program (NFIP).
  • Make an emergency plan for your household. This should include your pets, so that you and your family know what to do, where to go, and what you will need to protect yourselves from flooding. Learn and practice evacuation routes, shelter plans, and flash flood response. 
  • Gather supplies, including non-perishable foods, cleaning supplies, and water for several days, in case you must leave immediately or if services are cut off in your area. Keep important documents in a waterproof container. 
  • Create password-protected digital copies. Protect your property. Move valuables to higher levels. Declutter drains and gutters. Install check valves. Consider a sump pump with a battery.

Flood Hazard Map

What to do During a Flood:

  • Evacuate immediately, if told to evacuate. Never drive around barricades. Local responders use them to safely direct traffic out of flooded areas.
  • Contact your healthcare provider If you are sick and need medical attention. Wait for further care instructions and shelter in place, if possible. If you are experiencing a medical emergency, call 9-1-1.
  • Listen to EAS, NOAA Weather Radio or local alerting systems for current emergency information and instructions regarding flooding.
  • Do not walk, swim or drive through flood waters. Turn Around. Don’t Drown!
  • Stay off bridges over fast-moving water. Fast-moving water can wash bridges away without warning.
  • Stay inside your car if it is trapped in rapidly moving water. Get on the roof if water is rising inside the car.
  • Get to the highest level if trapped in a building. Only get on the roof if necessary and signal for help once there. Do not climb into a closed attic to avoid getting trapped by rising floodwater.

Flood Water

What to do After a Flood:

  • Pay attention to authorities for information and instructions. Return home only when authorities say it is safe.
  • Avoid driving except in emergencies.
  • Wear heavy work gloves, protective clothing and boots during clean up and use appropriate face coverings or masks if cleaning mold or other debris. 
  • People with asthma and other lung conditions and/or immune suppression should not enter buildings with indoor water leaks or mold growth that can be seen or smelled. Children should not take part in disaster cleanup work.
  • Be aware that snakes and other animals may be in your house.
  • Be aware of the risk of electrocution. Do not touch electrical equipment if it is wet or if you are standing in water. Turn off the electricity to prevent electric shock if it is safe to do so.
  • Avoid wading in floodwater, which can be contaminated and contain dangerous debris. Underground or downed power lines can also electrically charge the water.
  • Use a generator or other gasoline-powered machinery ONLY outdoors and away from windows.

For more flood information, go to Flood Information.

Landslide

Landslides occur when the soils of a slope, such as a hillside or mountain, become unstable. When this happens, the soil slides down toward the base of the slope, damaging or destroying structures built on the moving soil or in its path. While landslides are often thought of as fast-moving events, some landslides may happen slowly over a long period of time. 

The types of materials that compose a slope and the steepness of the slope help determine the overall risk that a landslide may occur. Soil stability and time also contribute to the risk of rockfall, which is of particular risk along roadways and trails where a path or highway has been cut into a hillside, exaggerating the angle of repose and increasing the likelihood of rockfalls. 

Landslides may be triggered by other hazard events. The shaking of an earthquake or the loss of soil stability as a result of earthquake-induced liquefaction can cause the soil to slide. Alternatively, precipitation can result in saturated soil and a loss of stability, or flowing water may erode the base of a slope. The risk of a landslide is often exacerbated in areas recently burned by wildfire, as the fire burns vegetation that can absorb water and hold back soil. Without the vegetation to stabilize a slope and prevent runoff, sediment and debris are more susceptible to sliding.  

Landslide hazards in Healdsburg are common, and generally occur as a result of heavy rainfall. Large earthquakes and improper grading or drainage practices can also cause landslides. 

Within Healdsburg, many of the swales or ravines that occupy the steep hill slopes may be capable of generating debris flows. Debris flows are most likely to originate on slopes underlain by sandstone or Glen Ellen sediments. Areas underlain by mudstone of the Great Valley Sequence are generally characterized by earthflows or slumps and are considered less likely to generate debris flows (Healdsburg 2009).

 Landslide Hazard Areas in Healdsburg:


 

Public Safety Power Shutoff (PSPS)

A Public Safety Power Shutoff is preventative system that utility companies use when they predict extreme weather conditions that could cause a fire. Among many other weather conditions, wind and trees can interfere with electrical transmission and distribution lines, which can ignite fires. While an extreme weather condition may not be occurring in your area, you should still be on the alert in case you are impacted by a Public Safety Power Shutoff. Go here to learn how our Electric Department is preparing for disasters and what you should do prepare you and your family for public-safety power shutdowns.

For a Statewide PSPS Factsheet, go to Prepare for Power Down.

Wildfire

Wildfires are uncontrolled fires spreading through vegetative fuels. Wildfires can be caused by human activities (such as arson or campfires) or by natural events (such as lightning). Wildfires often occur in forests or other areas with ample vegetation. In areas where structures and other human development meet or intermingle with wildland or vegetative fuels wildfires can cause significant property damage and present extreme threats to public health and safety. The risk to residents and property from wildfire is of significant concern. Wildfire danger is a major threat across the forested, fuel-rich area. High fuel loads in the wooded areas, along with geographical and topographical features, create the potential for both natural- and human-caused fires that can result in loss of life and property damage. These factors, combined with natural weather conditions common to the area, including periods of drought, low relative humidity, and significant winds, can result in frequent and sometimes catastrophic fires. Any fire, once ignited, has the potential to quickly become large and out of control. 

Wildfire severity is categorized into three zones: moderate, high, and very high. Healdsburg has no areas located in the very high severity zone. Per an exposure analysis completed for the City’s LHMP, over 50 percent of the city’s critical facilities, about 30 percent of residential structures, and almost 25 percent of the population are in a moderate or high wildfire severity zone. 

Risks, or the harm or losses, that are likely to result from exposure to wildfire include: 

  • Casualties (fatalities and injuries) 
  • Utility outages 
  • Economic losses for repair and replacement of critical facilities, roads, buildings, etc. 
  • Indirect economic losses, such as income lost during the downtime that results from damage to private property or public infrastructure 
  • Loss of natural and cultural resources 
  • Smoke and air pollution 
  • Creation of more favorable conditions for other hazards such as flooding, landslides, and erosion during the subsequent rainy season

Fire Hazard Severity Zones: