MyHazards Tool
MyHazards is a tool for the general public to discover hazards in their area (earthquake, flood, fire, and tsunami) and to learn steps to reduce personal risk. Users can enter an address, city, zip code, or a map location. The map enables users to zoom and scroll to their desired view and presents information on the risks identified within the search radius, along with recommended actions.
- EARTHQUAKE
Earthquake is the sudden shaking of the ground caused by the passage of seismic waves through the earth. Seismic waves are produced when energy stored in the earth’s crust is suddenly released, usually when rock masses strain against one another and suddenly fracture and “slip.” Earthquakes occur most often along geologic faults, where rock masses move in relation to one another. Three major faults (San Andreas, Maacama Garberville, and Bartlett Springs) pass through Mendocino County, which also marks the start of the Cascadia subduction zone.
The San Andreas fault has the near-highest probability of an earthquake greater than 7.8 magnitude in Mendocino County, with a greater than 10% annual probability. A smaller earthquake on the Maacama Garberville fault also has a greater than 10% annual probability.
Eight significant (greater than 4.5 magnitude) earthquakes have occurred in and near Mendocino County over the last sixteen years.
Stay Safe!
In most earthquakes, you will reduce your chance of injury if you DROP, COVER, HOLD ON when you feel shaking or get an alert. You may have to take an alternative protective action, depending on your situation and environment.
- Drop: Wherever you are, drop onto your hands and knees. This position helps to keep you from being knocked down and allows you to crawl to shelter.
- Cover: With one arm and hand, cover your head and neck. If there is a nearby desk or table, crawl under it for shelter. If there is no shelter, crawl next to an interior wall away from windows.
- Hold On: If you’re under shelter, hold onto it with one hand. If there’s no shelter, bend over and hold on to your head and neck with both arms and hands.
Living on Shaky Ground provides more information on how to survive earthquakes in Northern California.
Prepare your home and prepare your family or those with whom you live [link to Make a Plan page] for an earthquake. - TSUNAMI
The northern California coast is the most tsunami-prone area of the continental United States. A 10-foot wave run-up would affect the entire coastal area of Mendocino County.
Stay Safe!
FIRST, know if you are in a Tsunami Hazard Zone and plan safe evacuation routes by checking out this map. Use tsunami hazard maps to identify safe evacuation routes/areas.
NEXT, If you are in a Tsunami Hazard Zone, evacuate by foot to higher ground immediately after a large local earthquake or when you get a tsunami alert. Ground shaking may be your only tsunami warning! Follow posted hazard zone signs to identify safe evacuation routes/areas.
Living on Shaky Ground and the Redwood Coast Tsunami Work Group provide more information on how to survive earthquakes in northern California. - FLOOD
Due to its varied geography and climate, Mendocino County has a significant number of potential flood sources. Riverine flooding and coastal flooding represent the largest local risk. Flooding is primarily the result of severe weather and excessive rainfall, either in the flood area or upstream.
Most floods in Mendocino County have occurred between November to April, but several have resulted from heavy rain events during July, August, and September.
Stay Safe!
During a flood or flood warning, evacuate immediately if told to by authorities. Do not walk, swim, or drive through flood waters. Just six inches of moving water can knock you down, and one foot of moving water can sweep your vehicle away. Turn Around. Don’t Drown! Learn more about protecting yourself during a flood here.
- WILDFIRE
Wildfire in Mendocino County is highly likely, with the eastern portion of Mendocino County facing the highest fire risk. Fire conditions arise from a combination of hot weather, an accumulation of vegetation, and low moisture content in the air. These conditions, when combined with high winds and years of drought, increase the potential for a wildfire. The potential for significant damage to life and property increases in areas where development is adjacent to densely vegetated areas.
From 2002-2018, there were 27 significant (>1,000 acres) wildfires in Mendocino County, some of which overlapped with neighboring counties. The majority of these past wildfire events in Mendocino County occurred in the late summer months (typically, June through October). Frequency of these wildfire events may increase because of increasingly drier conditions caused by climate change.
Stay Safe!
Monitor active wildfires near you and sign up for MendoAlert, so authorities can reach you. If an evacuation is anticipated, follow these steps to give your home the best chance of surviving a wildfire. Leave as soon as evacuation is recommended by fire officials to avoid being caught in fire, smoke, or road congestion. Do not return to your home until fire officials determine it is safe.
Six P’s of Evacuation
- People, pets
- Papers, phone numbers, important documents
- Prescriptions, vitamins, eyeglasses, contact lenses
- Pictures, irreplaceable memorabilia
- Personal computer hard drive, disks/thumb drives
- Plastic (credit cards, ATM cards) and cash
- SEVERE WEATHER
Severe weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life. High wind and heavy rain are the two types of severe weather events that typically impact Mendocino County. These severe weather events can happen anywhere in the county. High wind and heavy rain can cause property and infrastructure damage, including the downing of power lines and loss of power. Fatalities are uncommon but can occur. Most of the precipitation falls during the winter; virtually no rainfall occurs during the summer months.
Since 2000, 19 heavy rain events and 12 high wind events have been reported in Mendocino County, causing a total of $34,417,000 in property damage.
Stay Safe!
When Power Outages are Expected:
- Fully charge mobile devices.
- Practice opening and closing your garage door manually.
- Fill your car with gas.
- Keep cash on hand.
During a Power Outage:
- Keep refrigerators and freezers closed.
- Turn off or disconnect appliances and electronics.
- Go to a community location with power when heat or cold is extreme.
- Have a generator? Follow safety instructions and use only as needed to save fuel.
- Learn more at PG&E’s Safety Action Center.
During Flood Events:
- Evacuate immediately if told to by authorities.
- Do not walk, swim, or drive through flood waters.
- Learn more about protecting yourself during a flood here.
Remember, just six inches of moving water can knock you down, and one foot of moving water can sweep your vehicle away. Turn Around. Don’t Drown!
- SLOPE FAILURE
Landslides, mudflow, debris flow, and rockfall are collectively known as slope failure, and may cause damage across Mendocino County. Although they rarely present a threat to human life, slope failures often result in property and infrastructure damage, as well as disruption of everyday services.
The most common type of slope failure in Mendocino County is debris flow, which occurs when slope material becomes saturated with water, and typically occurs during winter months.
Since 2000, Mendocino County has experienced three slope failure events. Slope failures are often triggered by other natural hazards, such as earthquakes, heavy rain, floods, or wildfires.
Stay Safe!
During a Severe Storm:
- Stay alert and awake.
- Make sure your communications devices are charged and ready if power goes out.
- Listen for unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together.
- Move away from the path of a landslide or debris flow as quickly as possible.
- Look upstream before crossing a bridge and do not cross the bridge if a mudflow is approaching.
Mudflows can move faster than you can walk or run.
- PANDEMIC DISEASE
There have been six pandemics since 1900, including COVID-19.
Stay Safe!
- PUBLIC SAFETY POWER SHUTOFFS
Electric utility companies have started massive, preemptive power shutoffs in high-wind events to avoid sparking fires (also known as public safety power shutoffs, or a PSPS). Your energy company makes the decision to turn off power by monitoring local fire danger conditions across California and taking into consideration a combination of weather and environmental factors. For more information on the factors used to determine PSPS events, visit www.prepareforpowerdown.com.
People with disabilities and others who are sensitive to cold or heat because of age or health conditions are at a greater risk when electrical power is unavailable. For more information on PSPS visit Pacific Gas & Electric’s Storms, Outages and Safety web page.
Stay Safe!
When a Power Shutoff is Expected:
- Fully charge mobile devices
- Practice opening and closing your garage door manually
- Fill your car with gas
- Keep cash on hand
- Keep refrigerators and freezers closed
- Turn off or disconnect appliances and electronics
- Go to a community location with power when heat or cold is extreme.
- Have a generator? Follow safety instructions and use only as needed to save fuel.
- Learn more at PG&E’s Safety Action Center.
