The Mistpouffers
On calm, misty days along the North Sea coast, people hear dull booms like distant guns rolling in from the sea.
What was reported
Along the coasts of Belgium and the Netherlands, people have long described mistpouffers, or 'fog belches': dull booms or thuds that seem to come from the sea, often on calm, hazy days. Similar sounds are reported in other countries under other names, such as the Barisal guns of Bengal and the Seneca guns of New York.
Before modern times, they were sometimes blamed on distant battles or storms out at sea.
Explanations offered
No single cause has been confirmed. Suggestions include distant thunder carried by layers of air over the sea, sonic booms, gas escaping from the seabed, and waves crashing in sea caves. Some booms today are traced to military activity, but not all.
- When
- Reported for centuries
- Where
- Coast of Belgium and the Netherlands
- Witnesses
- Coastal residents and fishermen
- Status
- Unexplained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.