December 4, 1998 transcript # 262-5
Subject(s): fog, smog, London
Title: Great Smog Of LondonOne of the great weather tragedies of all time happened on this weekend in 1952. It was a strangely quiet tragedy. Who'd have thought that fog could kill thousands of people? But this was not the fog of poets -- it was London's Great Smog, a lethal combination of fog and smoke. Hi, I'm Dave Thurlow from the Mount Washington Observatory and this is The Weather Notebook.
Londoners were used to fog for centuries, thanks to the city's cool maritime climate. But when England ran low on trees in the 1600's, and most city dwellers switched from wood to coal for heat, the fog, now smog, got nasty. By the 1800's, Londoners accepted the smog as part of life. This messy situation continued for another century, the culmination coming on December 4, 1952, when a large high-pressure center parked over London. The high formed an inversion, a shallow layer of cool air that trapped pollution near the ground. In one day, visibility was down to a few feet through a dense yellow cloud. Bicyclists found themselves covered in soot.
By Sunday the 7th, visibility was one foot. Movies had to be canceled because people couldn't see the screen. Strangely, there were no official warnings on radio or TV. Finally, the four-day siege ended as the inversion broke up, but it left 4,000 people dead, mostly from respitory and cardiac distress.
The Great Smog forced Londoners to convert to low-sulfur fuels like natural gas. Thanks to these changes, London fog remains a tradition, but the Great Smog is a thing of the past.
The Weather Notebook's contributing writer is Bob Henson. Visit our website at weathernotebook.org. for information on all topics presented here on the show; which is underwritten by Subaru with major support from the National Science Foundation.
Definitions of other types of Fog