Halfway through winter: where’s the snow?

For anyone who likes cold weather it has been a dreadful winter so far with no snow falling or lying in this part of Britain.

Shoulder of Mutton Pond, Wanstead Park by Scott Whitehead
An inversion during the first half of December saw the edges of ponds in Wanstead Park begin to ice up

A very mobile synoptic regime has seen numerous vigorous depressions blowing in off the Atlantic bringing flooding misery for many as swollen rivers burst their banks.

The predominantly maritime air over us has meant that even air frosts have been few and far between.

Since December 1st, Wanstead has recorded just 7 air frosts – half the number of last year. The coldest night was just -2.9C , warmer than the -6.9C recorded by this point last January.

The current mean temperature this winter to January 14th is 6.6C with rainfall 133mm – statistics that are remarkably similar to the winter of 1985/86 (mean 6.8C rainfall 130mm). That December and January was followed by a very cold February – the 4th coldest in a series stretching back to 1881.

However, before any coldies reading this get excited it should be noted that this season is also remarkably similar to winter 1989/90 (mean 6.8C, rainfall 128mm), which was followed by more stormy weather, including the Burns’ Day Storm, and the warmest February on record in this region.

Screen shot 2014-01-14 at 12.44.54Further scrutiny of stats for the Wanstead area reveal other years were similar. Using my method for finding patterns stretching back over 50 years to forecast this winter I picked out years that were +/- 10% of the mean. From these I then weeded out the seasons where the rain was +/- 10% of the 2013/14 rainfall total. This gave a list of five other winters with similar temperature and rainfall. Leaving aside 1985/86 and 1989/90 the other winters weren’t anything special with ‘snow lying’ days below the median for this area of six.

As I write this there are tentative signs on the weather models that a Scandinavian high may begin to form next week, introducing colder air from the east – exactly what we need to precipitate snow. However, they are just tentative signs and the cold air may never reach this far west anyway. Bear in mind also just how strong the influence from the Atlantic has been so far this winter. The Met Office have said the storms have been the worst in 20 years – which takes us back to the year in the above table of 1993/94. The only snow lying in that DJF season occurred in a short cold snap around February 15th – though, admittedly, an impressive fall of snow happened the previous November.

So, in summary, the probability at this point of at least one fall of snow before the end of February could be put at 75%. No snow: 25%. Abundant snow: 25%.

Tree damage by the war memorial in Wanstead High Street by Scott Whitehead
Damaging gusts associated with the depression on December 23rd felled this tree by the war memorial in Wanstead High Street

While compiling the figures I found that for my winter forecast to be correct would need a second half to winter exactly the same as 1985/86.

Some comparisons have been made between this winter and the balmy winter of 1988/89 – though that winter, the second warmest in the 1960-2014 series up to this halfway point, was a full degree warmer than this season and much drier, with only 30.9mm falling in over 6 weeks.

The culprit of the dry weather of that season 24 years ago was the influence of a very strong European high pressure which ‘blocked’ weather fronts from reaching this part of the UK, sending a conveyor belt of depressions skirting over Scotland bringing incessant rain instead of snow to Cairngorm resorts.

The nature of the weather this time round has been very different. Though December started with a strong anticyclone over Europe fronts associated with very deep depressions off the Atlantic have made inroads deep into the continent.

A classic Genoa low brought over 2 metres of snow above about 1,000m on Christmas day to resorts on the south side of the Alps. The nature of the airflow subsequent to that, however has brought some very high temperatures for the year.

Scottish and continental European winter sports enthusiasts will remember the season of 1988/89 well for all the wrong reasons, with little snow falling before March. I can vividly remember some amazingly cheap skiing holidays advertised on Teletext in January 1990. One deal was a week to Andorra for £19, including flights, transfers and half board in a 3-star hotel. A few of the lads in my A-level economics class took full advantage – only to return with tales about snowless mountains, sprained knees and wrecked skis, though it’s not clear how much of an influence the duty-free booze had.

Although many resorts were already investing in artificial snowmaking it was this season that quickened the pace of investment in snow cannons.

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200 years ago: the last Thames Frost Fair

The Frost Fair of 1814 on the River Thames in London. Painting by Luke Clenell, entitled The Fair on the Thames, February 4th 1814
The Frost Fair of 1814 on the River Thames in London. Painting by Luke Clenell, entitled The Fair on the Thames, February 4th 1814

It is 200 years ago this month that London enjoyed its last frost fair.

Weeks of hard frost from the day after Boxing Day was enough to freeze the river between the old London Bridge and Blackfriars, enabling dozens of opportunist London traders to set up stalls and booths selling souvenirs, drinks and food.

Unlicensed gambling, drinking and dancing was the order of the day for those brave enough to venture on to the ice. A sheep was roasted on the ice with the public charged to look at it, and charged again for a slice of “Lapland mutton”. At one point an elephant was led across the ice at Blackfriars.

The ice was however, not very stable. Boatmen deprived of an income charged visitors a penny to cross planks to get on to the ice. They were on hand to rescue two women who fell through, although a plumber carrying lead was not so lucky.

Though changes to the flow of the Thames has vastly reduced any chance of a frost fair being repeated I’ve often wondered what the day to day climate would have to be like to freeze the Thames as it did in 1814.

Luke Howard’s Climate of London provided a starting point. His pioneering measurements of the atmosphere taken outside his laboratory by the River Lea in Stratford, though not as accurate as today’s readings, provide an excellent insight into just how cold the season was.

Winter 1813/14 and 1962/63
This line chart shows that the winters of 1813/14 and 1962/63 bore some resemblance

I was surprised to find that the stats compare well with the winter of 1962/63 – the coldest winter in recent memory. Obviously Howard’s readings would not have been as accurate as today’s – his thermometers were initially suspended in a laurel bush to shield solar radiation – but they would still have been close.

I have converted his readings  in Fahrenheit to Celsius and plotted them on a spreadsheet here. As well as records of temperature, wind, rain and moon phase Howard also included any notable weather events in his diaries from both home and abroad.

The winter of 1813/14 started mild. On December 16th he noted that “bees quit the hive in unusual numbers for the season”. During the following days up to Christmas Day wind and rain alternated with misty, occasionally frosty, mornings – probably not unlike some of the weather we experienced last month.

However, Boxing Day brought a big change: “Since the 26th we have had a succession of thick fogs with a calm air or at most a breeze from the NE. Yesterday the air cleared a little and today has been fine; a display of cirrus clouds with much red in the morning and evening sky,  the peculiar smell of electricity has been perceptible of late when the air cleared up at sunset.” Howard goes on to report that there was an eruption of Mt Vesuvius in Italy.

The beginning of January saw the mists thicken into heavy freezing fogs: “The mists which have again prevailed for several days and which have rendered travelling dangerous.”

The view across to St Paul's Cathedral from Bankside at low tide by Wanstead_meteo
The view across to St Paul’s from Bankside at low tide. Images of what it looked like this month in 1814 can be seen on the Corporation of London’s website

In those days, with cloud identification in its infancy, Howard identified the fog as stratus and noted with wonder the formation of rime frost on everyday objects: “The air has been in effect loaded with particles of freezing water such as in a higher region would have produced snow.  These attached themselves to all objects crystallizing in the most regular and beautiful manner. A blade of grass was thus converted into a pretty thick stalagmite some of the shrubs covered with spreading tufts of crystals looked as if they were in blossom while others more firmly incrusted might have passed for gigantic specimens of white coral.”

By January 5th  a “deep snow brought by an easterly wind had reduced the whole scenery to the more ordinary appearances of our winter”.  More snow followed on the 6th and piled into drifts on a strengthening NE’ly. The biting gusts presented Howard with yet another new winter phenomenon: snow rollers:  “With the temperature at the surface 33 or 34F presented an amusing phenomenon which was pointed out by my children. Instead of driving loose before the wind it was collected occasionally into a ball which rolled on, increasing till its weight stopped it. Thousands of these were to be seen lying in the fields some of them several inches in diameter”.

On the 9th Howard describes a misty morning and a snowy landscape that had a “bluish tint”. The “blueness” of the air is possibly down to the sheer cold – it was -13.3C that morning. I’ve seen something similar, a bluish hue to the air, on very cold mornings in the Alps. Howard notes that the minimum on the surface of the snow that night, the coldest of that winter, was -14.4C.

The River Lea close to where Luke Howard's laboratory stood by wanstead_meteo
The River Lea close to where Luke Howard’s laboratory stood

On the 11th a “very red” sunrise was observed . By the 12th Howard describes the Arctic scene from his laboratory: “The River Lea is now firmly frozen and the Thames so much encumbered with ice that navigation is scarcely practicable.” Howard also notes on this date that the snow in upper parts of Hampshire and “on the Hind Head” had fallen to a depth of 15 feet in places.

A slight thaw was noted on the 16th from the warmth of the earth. More snow fell on the 18th and 19th. Snow on the 20th was accompanied by a strong NE’ly. On the morning of the 21st Howard noted drifts “many feet deep”.

The 22nd to the 25th saw more outbreaks of snow before the wind swung into the SW on the 26th with snow followed by rain – the cold spell was beginning to lose its grip. Howard notes on the 29th: As the barometer began to rise the wind came round by SW to NW and blew with great violence till near morning”. Classic freeze/thaw conditions followed over the next few days before the real thaw, and the end of the frost fair, arrived on February 5th. Howard notes: “Crimson sky at sunrise hollow wind snow and sleet. 6th A gale from SW with showers of rain at evening.”

Sunset from Southwark Bridge overlooking St Paul's Cathedral by WansteadMeteoThe rest of February, and meteorological winter, appears fairly nondescript. Howard notes that on the 12th a gunpowder explosion resulting in a fire at the Custom House, 5 miles south, caused a  “shower of fragments of burnt paper”. Sharp frosts and misty mornings prevailed to end of month, Howard noting the “clear orange twilights”, probably caused by the eruptions in Italy that formed a new crater on Vesuvius. Howard mentions a letter he received from Heligoland on February 21 which had also seen intense frost that was preceded by thick fogs and heavy falls of snow. The latter was 10 and 12 feet deep – the frost lasting six weeks.

Howard wrote his own account of the frost fair…

“The Thames Frozen Over

January 15: The masses of ice and snow had accumulated in such quantities at London Bridge on the upper side yesterday that it was utterly impossible for barges or boats to pass up. During the whole of this week that part of the Thames below Windsor Bridge called Mill River has been frozen over and has been crowded with persons skaiting.

February 3: The confidence of the public in the safety of the passage over the frozen surface of the Thames was yesterday increased. All the avenues from Cheapside to the different stairs on the banks of the river were distinguished by large chalked boards announcing A safe footway over the River to Bankside and in consequence thousands of individuals were induced to go and witness so novel a spectacle and many hundreds had what we cannot help terming the fool hardiness to venture on the fragile plain and walk not alone over but from London to Blackfriars Bridge. Several booths formed of blankets and sail cloths and ornamented with streamers and various signs were also erected in the very centre of the river where the visitors could be accommodated with various luxuries. In one of the booths the entertaining spectacle of a sheep roasting was exhibited

February 7: Friday several printers brought presses and pulled off various impressions which they sold for a trifle eg Printed to commemorate a remarkably severe frost which commenced December 27, 1813, accompanied by an unusual thick fog that continued eight days and was succeeded by a tremendous fall of snow which prevented all communication with the Northern and Western Roads for several days. The Thames presented a complete field of ice between London and Blackfriars Bridges on Monday the 31st of January, 1814. A Fair is this day February 4, 1814, held and the whole space between the two Bridges covered with spectators. This field of ice was indeed a very rugged one consisting of 1 masses of drift ice of all shapes and sizes covered with snow and cemented together by the freezing of the intermediate surface. The deceitfulness of the latter caused as is too common on such occasions the loss of some lives by drowning. The following passage announcing the opening of the river soon after is worthy of preservation on account of the spirit in which it is written.

February 11: We are happy to see the lately perturbed bosom of Father Thames resume its former serenity. The busy oar is now plied with its wonted alacrity and the sons of Commerce are pursuing their avocations with redoubled energy. Cheerfulness is seated on the brow of the industrious labourer those who were reduced to receive alms as paupers again taste the sweets of that comparative independence with which labour crowns the efforts of the industrious. What a fruitful source of congratulation does this prospect afford nor can the contemplative mind dwell on the subject without feeling gratitude to that beneficent Being who in a time of such calamity opened the hearts of the benevolent to administer from their abundance to the necessities of their poorer brethren and thus add cement to the bond by which all mankind are linked together. The mischief done on the river during the late frost is greater than can be remembered by the oldest man living. Among the craft alone it is calculated to amount to upwards of 10,000 independent of the damage sustained by the cables tackle & of the shipping.”

 

Wanstead Weather: 2013 review

The mean temperature of 10.7C makes 2013 0.5C colder than the 1981-2010 average. And makes the year 46th warmest in the series going back to 1881.
Rainfall of 554.9mm is 92% of average for a year in this area, making it the 68th wettest in the series back to 1888. Some areas of the British Isles have been considerable wetter – this just reflects how variable rainfall can be.
Though the year appears fairly average it masks some notable events…
A couple of notable falls of snow were observed in January and February
A couple of notable falls of snow were observed in January and February

January saw a couple of notable falls of snow, the first of which arrived on the 18th. By the morning of the 21st there was 13cm lying.

February saw a further snowy spell with 5cm falling on the 10th – but this only lasted a couple of days.
The mean temperature for March of 3.6C made it the coldest since 1892, the 3rd coldest in the series since 1881.
After a cool and dry spring and early summer July surprisingly turned out to be the warmest since 2006 – the mean temperature of 20.7C being the third warmest in the series going back to 1881. The warmest day of the year occurred on 22nd when 34C was recorded. This was followed by a very potent thunderstorm in the early hours of 23rd.
Autumn overlooking The Temple in Wanstead Park, by Wanstead Meteo
Autumn overlooking The Temple in Wanstead Park

An average August and September saw a couple of notable rainfall events with 32.8mm on 24/8 and 32.6mm on 13/9 being the the 27th and 28th highest 24hr totals in a series going back to 1961. In the August event Maldon in Essex saw in excess of 100mm leading to flooding. What made it more noticeable is that these events occurred during dry spells.

The end of October saw the St Jude storm blast through Wanstead. The strength of the gusts saw the demise of a few mature limes on Christchurch Green as well as trees in Wanstead Park.
So the stats…
Temperature (°C):
Mean (min+max)   10.7
Mean Minimum     6.7
Mean Maximum     14.7
Minimum          -7.0 day 16/01
Maximum          34.0 day 22/07
Highest Minimum  18.7 day 22/07
Lowest Maximum   -0.6 day 16/01
Air frosts       53
Sunset on Wanstead Flats by Wanstead Meteo
Sunset on Wanstead Flats

Rainfall (mm):

Total for year  554.9
Wettest day      32.8 day 24/08
Rain days        158
Wind (mph):
Highest Gust    47.2 day 28/10
Average Speed    2.9
Wind Run         25327.8 miles
Pressure (mb):
Maximum          1039.3 day 26/11
Minimum          974.9 day 23/12
Days with snow falling         25
Days with snow lying at 0900   12

Wanstead Weather – December 2013

Trees in fog by WansteadMeteo
The beginning of the month started with lots of calm, quiet weather with fog and night frosts. A high pressure inversion so not a proper ‘cold spell’

December was warmer than average with a mean temperature of 6.5C (0.9C above the 30-year average) – ranking it 33rd in the series since 1881. Rainfall of 81.9mm was 154% of average – ranking it 22nd in the series.

The month was 1C warmer than last December – with 84% of the rain that fell in December 2012.

Despite it ‘feeling’ like it has been the stormiest December for some years this month was not as windy as December 2012. To illustrate this the ‘wind run’ for this month (the number of revolutions of the anemometer) was 2408.7 miles. Last December was 2654.5 miles, in other words last December was 10% more windy.

Air frosts: 4

Ground frosts: 11

Thunder: 1

Small hail: 1

MetDesk rain radar for 23rd
The rain on the evening of the 23rd was heaviest to the south and west of us – with 75mm in the Warlingham area of Surrey. Flooding and high winds caused hundreds of thousands of power outs in Sussex and Kent