Marine Dense Fog
NOAA Storm Events type · 22 records since 2012 · marine zones
The National Weather Service defines marine dense fog as: "Water droplets suspended in the air just above the Earth’s surface, resulting in a fatality, injury, or damage, over the waters and bays of the ocean, Great Lakes, and other lakes with assigned specific Marine Forecast Zones." NOAA's Storm Events Database holds 22 marine dense fog records from 2012 through June 30, 2026, with 13 deaths recorded.
How the National Weather Service files marine dense fog
Water droplets suspended in the air just above the Earth’s surface, resulting in a fatality, injury, or damage, over the waters and bays of the ocean, Great Lakes, and other lakes with assigned specific Marine Forecast Zones. This fog reduces visibility to values equal to or below locally/regionally established values for dense fog (usually less than one mile).
National Weather Service Instruction 10-1605, Storm Data Preparation (July 26, 2021), Appendix A, entry 30
Source: National Weather Service Instruction 10-1605. Read the instruction (PDF).
Marine Dense Fog, 2012 to 2026
Records per year (2026 to June 30, 2026).
- recorded, no damage figure
- under $10 million
- $10 million or more
- $100 million or more
- $1 billion or more, or 100 deaths
- $10 billion or more, or 1,000 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 222012 to June 30, 2026
- Deaths
- 134 injuries
- Damage, 2025 dollars
- $81Kas filed (scale steps before 1993)
Source: NOAA NCEI Storm Events Database, records through June 30, 2026. Search the record at NCEI.
When do marine dense fog records happen?
The busiest month is August.
The values, month by month
Jan 3 · Feb 3 · Mar 1 · Apr 1 · May 3 · Jun 3 · Jul 1 · Aug 5 · Sep 1 · Oct 0 · Nov 1 · Dec 0 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.