Perranporth beach in Cornwall was closed to the public after a World War 2 bomb was discovered on Saturday afternoon.
Devon and Cornwall Police said the device washed up and could have been a result of the recent UK storms, the BBC reports.
According to West Briton, the bomb has now been detonated.
Speaking to the newspaper, Tom Job, manager of beach bar The Watering Hole, said: "The whole beach from the surf club was cut off and only the police and bomb squad were allowed on.
"There wasn't a massive explosion, but there was lots of smoke."
Walkers have been warned not to touch unidentified metal objects found on British beaches after police revealed unexploded bombs are the latest danger caused by the stormy weather.
Sergeant Lee Henderson of Devon and Cornwall Police told the Daily Mail: "Ferocious seas and weather are thought to be responsible.
"There is also the potential for further bad weather to unearth more devices.
"The bombs may still be very dangerous and people should not touch them but call police officers immediately."