Category Archives: weather in the media

Collapse of the Weisshorn glacier in 1819

Two hundred years ago this December a huge part of the Weisshorn glacier in Switzerland crashed down several thousand feet to the valley below.

saas fee glacier
A glacier above the village of Saas Grund, Switzerland. Viewed from below I am always struck by how precarious they look.

At 6am on December 27th 1819 the villagers of Randa, near Zermatt, were awoken as millions of tonnes of snow and ice swept away boulders, rocks, gravel and mature larch trees. Though the debris missed the village the force of the slide created a blast of air that moved entire buildings and their contents, burying 12 people, all but two of whom escaped with their lives.

Eyewitnesses described the noise of the falling mass as the loudest thunder and said a bright flash accompanied the slide before darkness once again enveloped the village.

First light revealed the utter devastation of the avalanche that have covered an area of pasture 2,400ft by 1,000ft by 150ft high.

It was not the first avalanche to bring disaster to Randa. In 1636 the village was destroyed by a similar avalanche when 36 people were killed. It is said that that occasion saw a much greater chunk of the flacier fall from the slopes of the mountain, at 14,783ft the 5th highest in the Alps.

Two other less serious falls happened in 1736 and 1786 but not precisely in the same place. This time only a small part of the glacier fell down.

Could a similar disaster happen again? With climate change and the nature of the Alps being constantly on the move it is possible. Earlier this month it was reported that part of a glacier on the Mont Blanc Massif, just 40 miles away as the crow flies, was on the brink of collapse.

I don’t have local figures but a look at the recent climatology in London shows that anomalies during the past couple of years – warmer than average summers and low rainfall – have been similar to what happened in 1819.

summer mean

summer rainfall

Of course the difference between now and 1819 is that we have early warning systems in place that can help prevent loss of human life in the event of a catastrophic avalanche.

weisshorn
The Weisshorn in the far distance seen from the slopes above Grächen

The night London slept out in the heatwave

Sleeping in heatwaves is never a great prospect even in an age where fans and air conditioning units are becoming more and more common.

In 1948, however, residents of Kensington and other areas of London were so hot and desperate to escape oven-like houses caused by temperatures well into the 90s that they decamped en masse into the streets and local parks to get some kip.

A report published in the Aberdeen Journal on Friday 30th July describes how folk down south were coping with the heat.

“The metropolis last night was like a large restless household—with all the lights ablaze, doors and windows thrown open, the family fretful, and endless pots of tea brewing far into this morning.

aspro heatwave ad Yorkshire Post and Leeds Intelligencer - Wednesday 13 August 1947“Perhaps one in ten among the 8,000,000 of us slept after midnight. For the rest, we tossed and turned and saw out this heatwave night, when temperatures were never below 71 degrees, a variety of ways. About midnight I walked past the gaunt old Edwardian mansions in Kensington. With the exception the lights that burned from every window, the scene was reminiscent of the early days of the Blitz.

“Families trekked across the roadway in varying stages of undress to their little bits of ornamental gardens. With them went camp beds, bed linen, umbrellas, “in case,” the children, and the household pets, choose a cool open-air camping spot and feel wonderfully adventurous and spartan in the process.”

“At regular intervals the adolescent members of the squatting colonies were dispatched to the tea and coffee stalls on the corner, and perhaps for the first time in years these traders ran out of stocks. On the Kensington-Chelsea boundary, where life becomes noticeably less inhibited and on occasions less swish, a mixed group of young artists was sleeping on the pavement off Fulham Road.

“Round the next corner, where many theatrical and film stars live, several had slung hammocks on their meagre front lawns – one actually suspended between the bathroom windows of two adjacent houses. Midnight street wear for both sexes was cool if unconventional —silk pyjamas, bath robes, tennis shorts, and one in kilt and bathing costume top who could have gone straight into the arena at Lonach.”

The temperature at Westminster that night never fell below 23.3C (73.9 F), a record for July that still stands.

The column goes on to describe the situation in the House of Commons where the heat had reached “almost Turkish bath intensity”.

“Some members were in natty tussore silk suitings, but this helped little, and it was many of their number who appealed to the Speaker to have more windows opened. The Speaker, panting like the rest of us, said they were all open. If they wanted more cool breezes from the Thames, members would have to smash the windows.”

This hot spell and others features in my Premier League of Heatwaves.

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London winter forecast 2018-19

Long range modelled forecasts have been all over the place of late and, looking at the underlying signals, it is easy to see why.

When I’ve produced these forecast in the past, in terms of QBO and ENSO data, there’s usually a lot of analogues to compare with. This year, however, seems to be an exception.

Considering QBO first I looked back over data to 1950 and found nothing similar for October. However, looking over the whole series the cyclical nature of this circulation may give some clue.

bestfit

Some 20 months were revealed, ranging from June 1959 to June 2015.  Using NOAA’s  Niño 3.4 region I narrowed this list down to the few that had an ENSO value of around +1 with a rising trend. With NOAA’s forecast of a Modoki El Nino (one that occurs in the central Pacific) this narrowed the list to just 1 period: June 2015. Considering maxima anomalies this would give the following winter.

winter 2018-19 max anomaly.PNG

The above would suggest there being a general cool down through December with a cold spell starting just before Christmas into the new year? And another cold spell end of January into the first week of February?

winter 2018-19 precip anomaly

The above precipitation anomaly chart would suggest a wetter than average December,  January and February, though February by much less so.

It’s been a very busy autumn so I’m keeping this short.

The below figures, particularly January and February, may be different in the event of an SSW occurring. In all then.

The mean:
December: +0.8C
January: -1.2C
February: -1.7C
Overall: -0.3C (broadly average)

Precipitation:
December: 158%
January: 155%
February: 120%
Overall: 134%

 

More hot air on bank holiday records

The media are up to their old tricks of flagging up their usual ‘hottest ever’ line; this time the May Day bank holiday.

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Today’s Guardian

Today’s Guardian informs readers that Monday could be the warmest ever May Day bank holiday, the quite unremarkable record high of 23.9C was set in 1999.

A closer look, however, reveals that dates of the holiday, which only began in 1978, are always moving. Like Easter the date shifts and can fall on any day between the 1st to the 8th. Only six early May bank holidays have occurred on the 7th. It is therefore difficult to compare like with like.

A more correct approach is to compare date records which, for the 7th since 1978, the highest is 27.1C in 2016. The highest temperature for the 7th going back 60 years is 28.5C in 1976.

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Past weather to rescue future reporting

“Worst floods ever!” Hyperbolic reporting of weather events is nothing new; whenever the UK is hit by the latest named storm breathless news anchors often try to portray atrocious conditions as ‘unprecedented’. This may soon change thanks to a project that uses citizen science.

Operation Weather Rescue, the citizen science project which last year processed Ben Nevis and Fort William data from between 1883 and 1904, has now recovered thousands of European observations from past Daily Weather Reports compiled from 1900-1903.

Though reanalysis data of the northern hemisphere back to 1851 have been available for some years the maps don’t give enough detail to be able to compare if an old storm has the same pressure characteristics as a modern storm. Evidence of impacts is restricted to fixed observations such as temperature, rainfall and archive press reports.

Weather Rescue: “We want to learn about the frequency of intense storms in the past to compare with now and these rescued observations will significantly improve our understanding.”

The latest release of data features pressure plots from June 1903 that tie in with the record-breaking 59-hour deluge that left much of the London Borough of Redbridge underwater. The following October, nationally, was the wettest month ever recorded in the UK.

Further recovery of these archived data, with the help of thousands of volunteers, will prove invaluable to our understanding of high-impact weather, and if storms are getting worse.

This latest example of Big Data could also offer huge benefits to the insurance and reinsurance industries, as well as planning engineers, as the resolution of climate models steadily improve.

But on a purely weather reporting scale it should also be possible to one day provide the media with a quickly accessible database of weather events going back over a century, enabling them to judge whether the latest storm really is the worst in 100 years.

In this age of clickbait journalism, however, I’m not holding my breath!

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