Environmental Risk Report for Honolulu County, Hawaii
Comprehensive environmental hazard assessment
Coordinates: 21.4588°N, 157.9747°W • FIPS: 15003
Risk Assessment for Honolulu County, Hawaii
About Honolulu County, Hawaii
Honolulu County is a county in HI known for its varied climate ranging from Mediterranean on the coast to alpine in the mountains. Its coastal location provides beautiful scenery but also creates unique vulnerability to storm surge and coastal flooding.
Our risk scores for Honolulu County are calculated using data from the Federal Emergency Management Agency (FEMA) National Risk Index, the U.S. Geological Survey (USGS) earthquake databases, the Environmental Protection Agency (EPA) AirNow program, and the National Weather Service (NWS) alert system. These federal datasets provide comprehensive coverage of natural and technological hazard exposure.
Notable historical events affecting this area include the 1992 Hurricane Iniki (Category 4, 6 deaths, $3.1B damage, devastated Kauai); the 2018 Kilauea Eruption (Destroyed 700+ homes, covered 13.7 square miles in lava); the 1946 Aleutian Tsunami (159 deaths in Hawaii, 57-foot waves hit Hilo). These events underscore the importance of environmental risk awareness and preparedness for residents and property owners.
Hawaii's isolated island geography creates unique hazard considerations including volcanic activity from Kilauea and Mauna Loa, tsunami exposure across the Pacific, hurricane vulnerability, and flash flood risk from steep terrain and intense tropical rainfall.
Notable Historical Events in Hawaii
Understanding Risk Factors for Honolulu County
🌊 Flood Risk
Honolulu County faces significant flood risk due to its coastal location. Storm surge from hurricanes and tropical systems can push water miles inland, while heavy rainfall events strain local drainage systems. FEMA flood zone maps identify multiple high-risk areas, particularly in low-lying neighborhoods near the coastline and waterways.
🌋 Volcanic Hazard
Honolulu County is within the Cascade Volcanic Arc, home to several active volcanoes including Mount St. Helens, Mount Rainier, and Mount Hood. Volcanic hazards include ashfall, pyroclastic flows, and lahars (volcanic mudflows) that can travel dozens of miles from the eruption site.
🌍 Earthquake Risk
Seismic hazard assessment for Honolulu County uses USGS earthquake data including fault line proximity, historical seismic activity, and geological survey information. While not in the highest-risk seismic zones, the area can experience tremors from distant earthquakes.
💨 Air Quality
Air quality monitoring in Honolulu County draws from EPA AirNow sensors measuring particulate matter (PM2.5), ozone levels, and other pollutants that affect respiratory health. Seasonal variations and agricultural or industrial activity can influence local air quality.
🔥 Wildfire Risk
Wildfire risk evaluation considers vegetation density, climate conditions, historical fire data, and terrain characteristics in Honolulu County. Seasonal weather patterns and local land management practices influence the area's fire vulnerability.
Other County Risk Reports in Hawaii
Compare environmental risk scores across Hawaii counties — flood, earthquake, wildfire and more