Winter 1739-40 is the second coldest on record within the CET series that goes back to 1659, behind only the Lorna Doone Winter of 1683-84 and slightly ahead of 1962-63.
Monthly CETs for 1739-40:
December; 3.2°C
January; -2.8°C
February; -1.6°C
Winter; -0.40°C
December 1739 as you can see here wasn't an exceptionally cold month really but January and February 1740 certainly were (200 years later, we would achieve a very cold January again in 1940 which up to that point was the coldest month of the 20th century but that's a month for another day).
1740 of course was the year of the infamous Great Irish Frost as well as the forgotten Irish Famine. Previously to 1740, we had a run of relatively mild winters so this season was a huge surprise out of nowhere for people in the UK and Ireland, also Europe.
It is estimated that between 20-38% of the Irish population in 1740 (2.4 million) were killed due to the famine that had occurred. This is around 300,000 to 480,000 deaths. The famine was caused by the extreme cold and the very wet weather that succeeded it. As a consequence of the weather, there were poor grain harvests, a shortage of milk and frost damage to potatoes. Ireland was the most severely affected by the famine in terms of mortality due to the grain and potato failure but the terrible effects from the weather were spread out across Europe.
According to the Irish Independent on March 4th, 2018:
The Dublin Evening Post reported an open-air ball held on the surface of the Boyne, where grandees participated in "several country dances on the ice, being attended by a large band of music".
The party mood didn't last as the cold snap outstayed its welcome. With the ports frozen, the coal supply to east coast households dried up. When the ice eased and imports resumed, coal prices spiked putting it beyond many. This sparked an orgy of illegal tree felling, with 14 arrested for chopping in the Phoenix Park alone. The coal merchants were accused of stockpiling and profiteering.
A series of failed grain harvests in the 1720s had pushed the poor into an ever deeper dependence on potatoes, which by 1740 had become the dietary mainstay of much of the populace. Before the Great Frost had even lifted, noting that the potatoes were frozen in the ground and in storage, Cork estate agent Richard Purcell chillingly predicted: "The eating potatoes are all destroyed, which many think will be followed by a famine among the poor, and if the small ones, which are not bigger than small peas and which be deepest in the ground, are so destroyed as not to serve for seed, I think this frost the most dreadful calamity that ever befell this poor kingdom."
By the end of February the frost had finally vanished, only for the weather to confound and dismay with another cruel twist. The big freeze continued, but it was a bone-dry freeze. As spring turned to summer, temperatures struggled upwards, but there was little respite from the drought, which was felt over a large part of Europe.
The failure of the potato crop caused a big jump in demand for grain, but the drought severely damaged the grain harvest so that wheat, oat and barley prices skyrocketed. For the ordinary person, the soaring grain prices could be directly measured in the shrinking size of the loaf of daily bread. As they had often done before in desperate times, the poor took to eating nettles as a proven source of nourishment. In Dublin, Drogheda and other towns, there were food riots and the looting of shops and storage depots.
The weather played more cruel tricks as Christmas 1740 neared. Blizzards in October and November were followed by torrential rain in December which in turn was followed by a sudden deep freeze. Billions of tons of water locked up as ice were suddenly liberated by a sharp warming which caused flash floods, propelling deadly miniature icebergs into the paths of boats and buildings.
The catastrophe came to a horrible head in the spring and summer of 1741, dubbed Bliain an Áir, or the Year of Slaughter. Starvation compounded a range of diseases and led to epidemics of 'flux' (dysentery), typhus and other ills.
1740 was likely caused by the eruption of Mount Tarumae, Japan in August 1739 (which had a volcanic explosivity index (VEI) of 5, very high) and volcanic eruptions on the Kamchatka peninsula in Russia. However, it remains a mystery what led to this extreme event.
A great book that is worth a read is Arctic Ireland: The Extraordinary Story of the Great Frost and Forgotten Famine of 1740-41 by Trinity College History professor, Dr. David Dickson. https://www.amazon.com/Arctic-Ireland-Extraordinary-Forgotten-1740-41/dp/1870132858
There are reports of temperatures in Ireland being well below our current record of -19.1°C at Markree Castle on January 16th 1881 with suggestions of near -30°C. I think it's more realistic to say that lowest temperatures could have been around -20 to -22°C considering our maritime climate. Like the thoughts of -30°C is just a bit too far out there and insane.
What makes 1740 even more remarkable than it already is from what you know here so far is that the 1730s was the warmest decade on record at the time in the CET, De Bilt (Holland) and Uppsala (Sweden) long term temperature series until being beaten over 260 years later in the 1990s. The mildness of the decade is confirmed by the early ice break-up dates for Lake Malaren and Tallinn Harbour. The rapid warming in the CET record from the 1690s to the 1730s and then the extreme cold year of 1740 are examples of the magnitude of natural changes which can potentially be recorded in long series. Consideration of variability in these records from the early 19th century, therefore, may underestimate the range that is possible.
https://www.researchgate.net/publication/226043410_Unusual_Climate_in_Northwest_Europe_During_the_Period_1730_to_1745_Based_on_Instrumental_and_Documentary_Data
Very in-depth paper on 1740-41.
https://www.clim-past.net/9/1161/2013/cp-9-1161-2013.pdf
It's suggested that the extreme cold was down to a very persistent Scandinavian High.
From 'The Little Ice Age' by Brian Fagan:
In late 1739, the NAO swung abruptly to a low mode. Blocking anticyclones shifted the depression track away from its decade-long path. Southeasterly air flows replaced prevailing southwesterlies. The semipermanent high-pressure region near the North Pole expanded southward. Easterly air masses from the continental Arctic extended westward from Russia, bringing winter temperatures that hovered near or below zero. Europe shivered under strong easterly winds and bitter cold for weeks on end.
For the first time, relatively accurate temperature records tell us just how cold it was. An extended period of below average temperatures began in August 1739 and continued unabated until September of the following year. January and February 1740 were 6.2C and 5.2C colder than normal (!). Spring 1740 was dry with late frosts, the following summer cool and dry. A frosty and very wet autumn led into another early winter. In 1741 the spring was again cold and dry, followed by a prolonged summer drought. The winter of 1741/42 was nearly as cold as that of two years earlier. In 1742, milder conditions finally returned, probably with another NAO switch. The annual mean temperature of the early 1740s in central England was 6.8C, the lowest for the entire period from 1659 to 1973.
Some extracts on the season.
Harrod's "Antiquities of Stamford" In the hard frost of 1740, at two different days, a sheep and a hog were roasted on the river Welland, where the ford is at the opening in Water Street. The printers also came and got much money by printing person's names who assembled there. The hard frost began Christmas Eve and lasted til Lady Day 1740; the greatest degrees of cold was on January 5th in the morning; it frequently relented in the forenoon but was sure to return at night; however it was not so intense as the frost of 1709, when the Adriatic sea was so frozen that it might be passed on foot, so that the Venetians been at war with the Turks their city might have been taken by a land army.
Dr Huxham of Plymouth December The weather in this month was altogether surprising; in the beginning we had a northeast wind and a severe frost, presently a rainy and turbulent south wind; in a very short time after a southwesterly and a great deal of rain, the barometer nevertheless rising. The 14th and 15th, the wind was northwest; the 16th, northeast and a return of the frost; the 19th and 20th, a violent southeast; on the 21st again, a stormy southwest; from that of an easterly, a cold northeast wind intervening, the 25th and 27th then a most severe storm from the east, with an exceeding severe frost and a constant exceedingly small snow to the very end. In an instant, a most piercing cold froze up everything, both within doors and without, nay, the very strongest kinds of wines were frozen; indeed whatever was exposed to the air instantly turned to ice. . People even shivered by the largest firesides nor could keep themselves warm in their very beds. January The severity of the cold still continued, such indeed, as was never known in this country. Although the first day of the month, there was a great thaw and a fall of rain, nevertheless the northeasterly wind and a most sharp frost instantly returned which lasted til the very end of the month and although the heat of the sun; all things thawed by day, yet by night were bound by a most rigid frost. The coldest days were the 11th, 15th, 16th, 17th , 18th, 26th, 27th, 28th; nay so severe was the frost which now prevailed that all kinds of wine being exposed out of doors which immediately turned to ice , nay, the very saltwater upon the shores was so, a thing this which very seldom happens in these parts. Innumerable trees and shrubs were cut off by the cold and even the very hardy furzes themselves. A vast number of seabirds flew hither and numbers from foreign countries , which had never been seen here before.
George Smith of Richmond (Surrey), a proctor to Queen Anne Thames froze over in 4 days, storm of wind 48 hours (30th Dec) Some people walked over the Thames (1st Jan) Frost continued till February 1st, when a thaw began in day, frost returning each night. Ice all gone in Thames upward but not broke about London (Feb 11th) Ice beings to run in Thames (13th Feb) Ice broke in Thames (17th) Ice gone at London (23rd) This was the severest frost I ever known and the most kindly thaw. No rain, roads good, all garden stuff destroyed. Hard frost again in March. A very backward spring, dry and dusty as summer, no considerable rain for 3 months past; the river a slow as ever known. (31st Mar) Very great storm of snow and wind from 10 to 2 (21st Apr) A very cold unkind season (30th Apr) Extraordinarily dry dusty and cold, very unpleasant season (31st May) The coldest weather ever known at Michaelmas, piercing cold (30th Sep) A very unkind year, no good fruit, nor warm weather ; winter severe; storms and frost with great snow."
What an unprecedented and extraordinary piece of history right here, just as much as Winter 1683-84!
