Published on 31 Mar 2014

Saharan dust falls across the UK

Saharan dust? Here in the UK? Really? Well, if you see a thin layer of dust on your car in the coming days, that is what it could be.

Since yesterday, lots of people have been sending me pictures on Twitter of their cars covered in dust. I noticed it too, on my journey to work this morning.

Whilst it doesn’t happen often, when it does, it is very noticeable – especially if you’ve just washed your car and it suddenly gets dirty again. 

The word 'DUST' written on car rear windscreen following Saharan sand deposited in England by strong south easterly winds
How does Saharan dust get here?

In order to work out how the dust got here, you need to take a look back at what the wind in the upper part of the atmosphere has been doing in recent days.

Sure enough, this weekend, the wind in the upper of the atmosphere over the UK was blowing in a southerly direction – all the way from north Africa and the Sahara Desert.

The image below from EUMETSAT, taken at around midday on Sunday, is an atmospheric motion vectors (AMV) product. It shows wind vectors at different heights derived by tracking the motion of the clouds and other atmospheric constituents.

sat_wind_EUMETSAT_wp

It shows that the wind in the upper part of the atmosphere (pink and red wind barbs) over the UK was blowing from southerly direction – all the way from north Africa and the Sahara desert.

How does the dust get into the sky?

Just as in other parts of the world, the wind can blow strongly over deserts too – whipping up dust and sand high into the sky.

The wind in upper part of the atmosphere then transports the dust in the direction in which it’s travelling.

So, as this wind was blowing towards us at the weekend, it brought the dust with it.

How does the dust get down to the ground?

In order for the dust to get from up in the sky down to the ground, you need something to wash it out of the sky, and that something, is rain.

When the raindrops fall, they collect particles of dust on the way down. Then when the raindrops land on something and eventually evaporate, they leave behind a layer of  dust.

So, if you spot a layer of dust on your car, have a think at just how far it’s travelled to get here!

If you take any pictures of Saharan dust, send them to me on Twitter – @liamdutton

 

 

Tweets by @liamdutton

3 reader comments

  1. SimonB says:

    Isn’t one of the theories as to how Foot & Mouth got here in 2001 that it came on Saharan dust? Should we be worried?

  2. callis says:

    They said this in the 50s &60s, turned out they were testing to see where WOMD could be airborne dropped on the UK

  3. Ashley Haworth-Roberts says:

    Is it certain that all areas which saw this dust had some light rain fall before it was seen? Can Saharan dust fall to the land surface without any rain or is rain essential? I was not aware that any rain fell in the London area between Sunday afternoon and Monday morning – though I did not view Met Office rainfall radar for the period in question.

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