The following hazards pose the most risk to development and life safety.

1. Wildfire Hazard: Humboldt County, like much of California, is susceptible to wildfires due to its warm, dry climate, and abundant vegetation. The risk is particularly high in the summer and fall when conditions are driest. The steep terrain in parts of the county can also exacerbate wildfire risk by allowing fires to spread rapidly and making them difficult to control. To manage this hazard, development in certain areas may be subject to building regulations which are designed to make structures more resistant to ignition from wildfires.

2. Flood Hazard: Humboldt County is crossed by several rivers, including the Eel River and Mad River, which can flood during periods of heavy rain. Coastal areas of the county are also at risk from coastal flooding and sea-level rise. The Federal Emergency Management Agency (FEMA) produces Flood Insurance Rate Maps (FIRMs) which identify areas of the county that are at risk of flooding, and these maps are used to apply appropriate building regulations to mitigate this risk.

3. Seismic Hazard: Humboldt County is located in a seismically active region and is intersected by several significant fault lines, including the Cascadia Subduction Zone and the San Andreas Fault. As such, it is at risk from earthquakes, which can cause ground shaking, surface rupture, and in some cases, soil liquefaction or landslides. Buildings in the county are subject to the seismic provisions of the California Building Code, which require structures to be designed and built to withstand the forces generated by earthquakes.

4. Fire Hazard: Apart from wildfires, the potential for fires starting within buildings themselves is another hazard. These can be caused by various factors including faulty electrical wiring, inappropriate use of heating equipment, misuse of flammable materials, or improper storage of combustible substances. To mitigate these risks, California’s Building Code specifies fire safety standards for new constructions, which include requirements for fire-resistant building materials, safe installation and maintenance of electrical and heating systems, and design of building layouts to provide clear escape routes in case of fire.