Loading
Dense fog
Persistent UK winter hazard. Driving and aviation are the prime risks.
Context
UK fog forms most commonly in autumn and early winter, particularly in valleys, by rivers, and along coasts. Dense fog (visibility < 200 m) closes airports and causes serial-collision pile-ups on motorways. Freezing fog (fog where droplets freeze on contact with surfaces below 0°C) compounds the hazard with rime ice on roads.
When this matters
Met Office fog warning, or you can directly see visibility dropping below ~500 m.
Before
- Allow extra time for road journeys. Don't try to "make up time" in fog.
- Test your fog lights in summer — they're often forgotten until too late.
- Plan alternative routes — A-roads in fog are often safer than country lanes.
- For aviation: check airport METAR / TAF before travelling. CAT II/III approaches are common at major UK airports but small airfields will close.
During
- Use dipped headlights, NOT main beam (main beam reflects off the fog and reduces your visibility).
- Use rear fog lights only when visibility is below 100 m — leaving them on otherwise dazzles other drivers.
- Slow down. Increase your following distance — UK fog pile-ups are almost always caused by people driving too close at too high a speed.
- If you have to stop on a motorway: pull off at the next exit. Don't stop on the hard shoulder unless absolutely essential.
- At sea: sound fog signals every two minutes. Switch to radar navigation. Listen for other vessels.
After
- If you witnessed a serious accident: call 999 with location and casualty count.
- Report visibility hazards to Highways England via the variable message signs in your area.
UK specifics — numbers, sources
- Met Office fog warnings: yellow → amber as visibility drops and area widens.
- Highways England traffic info: trafficengland.com or 0300 123 5000.
- HM Coastguard: 999 → Coastguard for any maritime fog emergency.
- NATS: nats.aero for UK aviation impact info.
General guidance. Your specific circumstances may vary — follow the Met Office, Environment Agency / SEPA / NRW, your local council, and emergency services for situation-specific direction. See the code of conduct for chasers in the field.