The London storms of July 1923
The period from the 6th-13th July in 1923 was very warm/hot and at times, but notably thundery.
In London though it was most notable for the spectacular thunderstorm of 9th-10th July 1923. As a slack area of low pressure stagnated over the southern UK for a few days before, temperatures rose to 29C on the 9th in both parts of London and also at Tunbridge Wells (Kent). The storm began at 11pm in the London area and lasted until about 5am, the next morning. There were 6900 lightning flashes seen in Chelsea, London in the 6 hour period, an average of nearly 1 every 3 seconds. Over 50mm of rain fell in a 15 mile wide strip from Hampstead, North London, which reported about 62mm, Kew reported 52mm and then south to the coast at Brighton, with as much as 82mm at Seaford (East Sussex); many houses were struck by lightning, and some caught fire; forty fire related calls were reported to the London Fire Brigade with a large house at Walton on the Hill (Surrey) completely destroyed. Interestingly an eye witness account suggested that this was caused by a ball of fire which dropped onto the house, so there is some suggestion it was caused by 'ball lightning'. A tramcar on the Victoria Embankment was also struck by lightning and caught fire. 3000 telephone lines were rendered out of order in the London area as well.
The brilliance and frequency of the lightning, the loudness of the thunder & the fact that it went on all night with torrential rain made it a formidable event for many. The continuous storm was really a series of seperate cells of course moving in a generally NNE direction which cut a swathe across Sussex and Surrey up into London. An observer at Eton described the lightning as being a beautiful violet colour, noting how 'the whole southern horizon was ablaze but at first there was only the occasional low rumble of thunder and not a breath of wind to ease the sweltering conditions'. Here the storm struck during the late evening and raged for eight hours. On occasion there would be a brief lull as one cell moved away before 'the pyrotechnics began again with renewed vigour'.
A Times corresondent described the storm as seen from Sydenham Hill in some detail. He noted how it reminded many soldiers of the war, still fresh in the minds of many then, from the trenches, bringing bad memories of that conflict back with it. A 'fireball' was also seen as well, possibly again an instance of ball lightning. Hail was also reported as well.
The storm however was not a plume event though, with an active cold front - as it did not move fresher clearer air through; it remained rather hot for a number of days longer in the southern UK before the hot sultry weather broke properly and it became cooler.
