British winter of 1946-1947
From Wikipedia, the free encyclopedia
The British winter of 1946-1947 was one of the most severe winters on record. Just as the country was recovering from post-World War II fuel and food shortages, it had to cope with prolonged frost and snow from 21 January to 16 March 1947.
Contents |
[edit] January
Two relatively short spells of cold weather - one in December 1946, the other in early January 1947 - led up to the winter.
An anticyclone that became anchored over Scandinavia around 20 January brought about the third and longest cold spell. This system blocked the eastward progress of Atlantic depressions and forced them south of the UK instead. This caused easterly winds to set in, bringing snow first to eastern and south-east England before extending across much of the country. Intensely cold conditions affected much of England and Wales in the final week of January; on the morning of the 30th the temperature at Writtle, Essex was -20 °C. The highest temperature that month for England and Wales was around 14 °C, and the lowest was a numbing -21 °C. On 30 January the Isles of Scilly were lying under about 18cm of snow.
[edit] February
Easterly winds persisted throughout the coldest February on record, with only brief breaks in the cold snowy weather. On no day did the temperature at Kew Observatory top 5 °C, and only twice in the month was the night minimum temperature above freezing. It was the coldest February on record in many places and, for its combination of low temperatures with heavy snow, bore comparison with January 1814.
In some parts of the country, snow fell on 26 days. It was often light and powdery so it easily formed deep drifts that affected roads and the railway network. New ways were tried to clear them. One method was to mount jet-turbine engines on towed trailers and angle the hot-air outflow of the engines towards the ground; these were hugely effective in clearing the snow from roads but the underlying surface melted too, so the experiment was rather short-lived.
Notably, in contrast, parts of western Scotland remained remarkably dry. Because of the persistent anticyclonic conditions, some places that were normally very wet had no rain at all. A completely dry month in western Scotland is uncommon and was unprecedented for February. Another unusual feature was cloudiness in the Midlands and south of England - a complete contrast to the north-west of Scotland, where the weather was unusually sunny.
At Kew, Nottingham and Edgbaston, there was no sun on twenty two days and, at Kew, there was none at all from the 2nd to the 22nd. Most places in the Midlands and southern England recorded sunshine totals less than half the average.
When skies did clear, night-time temperatures plunged. A minimum of -21 °C was recorded at Woburn in Bedfordshire early on the 25th. Without the cloudcover, the month would almost certainly have been even colder than it was, certainly at night.
[edit] March
March proved to be even worse. In the first half of the month, there were more gales and heavy snowstorms. On 4 and 5 March, heavy snow fell over most of England and Wales with severe drifting. On 6 March, drifts measured five metres deep in the Pennines and three metres in the Chilterns. In some places, glazed frost occurred. On 10 and 11 March, southern Scotland had its heaviest snowfall of the winter and, on the 12th the Scottish Highlands reported drifts more than seven metres deep.
Meanwhile, mild air with a temperature of 7-10 °C edged into the extreme south-west of the UK on 10 March, bringing rain. The ensuing thaw was rapid - by the evening of the 11th, vast areas of southern England were under water. After weeks of frost, the ground was frozen hard. The rain and meltwater couldn't soak into the ground - surface run-off was its only option.
The warm air spread northwards and eastwards. Meltwater from the Welsh mountains poured into the valleys of the Severn and Wye, flooding Herefordshire and Gloucestershire. The rivers of the English Midlands burst their banks and, by 13 March, Fenland rivers were close to overspill.
On the 15th, a deepening depression from the Atlantic approached the UK with rain and severe gales. During the afternoon of the next day, brisk winds over southern England reached 50 knots, with gusts of 80-90 knots. Buildings were damaged and waves were whipped up on floodwaters. In East Anglia, where the major rivers flow north-eastwards, the south-westerly wind drove their waters ahead and waves pounded the dykes. Water levels rose, the dykes breached and flooded most of Fenland. Troops were called in, but could do little to stop water racing through the breaches.
River levels rose relentlessly. For example, the Trent burst its banks at Nottingham on 18 March, flooding hundreds of homes - many to first floor level. When floodwater reached the tidal part of the Trent, it was impeded by a spring tide, and the whole of the lower Trent valley was flooded.
The floods in the West Country subsided after the 20th, but rivers continued to rise in eastern England. The Wharfe, Derwent, Aire and Ouse all burst their banks and flooded a huge area of southern Yorkshire. Selby was almost completely under water - only the ancient abbey and a few streets around the market place escaped inundation. Seventy per cent of all houses in the town were flooded.
The cold and snowy weather had ended, but the floods continued into the spring.
