Space Weather Preparedness Strategy: A Faraday Cage?

SunandMagnetosphere_400 203804 courtesy of NASA

The sun interacting with the Earth’s magnetosphere, courtesy of NASA

So, after my last post, where I was writing about the UK government’s report on space weather, this post is about the linkup that’s made in prepping circles to a Faraday Cage (FC), and how to make one. And about a couple of expedient ( read “emergency”) FCs if the Met Office tell us that a ginormous storm is on the way.

We need to know what an FC actually is. This is the Wiki definition, and I’ve listed the important bits below:

  • the enclosure is formed by conductive material.
  • it works if the conductor is thick enough and if any holes are significantly smaller than the wavelength of the radiation.

But … but … hang on. The recommendations about whether or not a Faraday cage is actually helpful to protect from geomagnetic storms/CMEs are really contradictory, and maybe this is because the science is so new. It got so confusing that I started to make a list of who thought they’d help, and who didn’t, in both the mainstream scientific websites and the preparedness websites. And I stopped that, almost straight away, so here’s what I’ve learned: there’s a huge amount of disagreement about whether FCs are of any use in protecting electrical and electronic equipment from geomagnetic storms. Nearly all the American discussions tend to be in terms of nuclear attack, whether by full scale war or just a few high-altitude explosions to use the EMP pulse against them. That’s the scenario in One Second After, William Fortschen’s novel (which is a really great read, very powerful) about just such a war.  There’s an Amazon link at the bottom of this page, and his own website is listed on my Links page.

Anyway  … I had no idea the disagreements on FCs were as wide-ranging as they seem to be, so I’m simply going to base the rest of this post on three statements:

Firstly, geomagnetic storms will continue to occur, as they always have done, and some of them, at some stage in the future, will be at least as strong as the Carrington Event of 1859. The Met Office has some helpful descriptions here (though see a couple of paragraphs below).

Secondly, the UK National Grid will very probably be disrupted to some extent, probably for months: at the very least, you should ensure your stocks of food, water, medicine, cash etc are sufficient to see you through the initial confusion of this break in supply, so that you don’t suffer too much (and can maybe help out a bit locally) while emergency supplies are distributed. If those emergency supplies don’t materialise for months, your well-stocked food cupboard could literally be a lifesaver for you.

Thirdly, after you’ve unplugged your electrical and electronic goods, you could indeed put them in a n FC – nothing I’ve read, anywhere at all, indicates that the cages attract electrical surges, so as long as you don’t make yourself suffer to build one, then why not? They might save your stuff. They might not be necessary, in which case your stuff will be safe anyway.

Hmm. Those “helpful descriptions” by the Met Office, referred to above in the first point. Are things really that rosy in the UK, compared to a lot of other places? Because our National Grid lines are short and the authorities have been upgrading transformers? I’d love to believe it, but I’ve always had a certain scepticism about government statements and government figures. Most people share that scepticism, to some degree or another. So while I no longer think that a geomagnetic storm is something that’s highly dangerous to me as a prepper, I do still think it’s worth taking some precautions against it, just in case, because I don’t 100% believe the government, to be frank. And in any case, it’s such a new area to be researched, all the answers aren’t known yet.

What if you had the chance to make a cage and didn’t do it, then all your stuff got wiped out by a geomagnetic storm? Even when the National Grid transformers are eventually replaced (in 6 – 12 months, in a bad storm? Who knows!) is your insurance company still making good on claims? If it’s gone bust, how’s the government’s fallback scheme going? Is it overwhelmed? How far back in the queue are you? This is the crux of the probability vs impact scenarios: I won’t even call this “low probability/ high impact”, because the probability seems to be higher than that, approximately 1% in any one year.

I should make it clear again that I’m completely ignoring the whole issue of high-altitude attacks by other states or by terrorists, or a full-scale nuclear war. If you search online, you’ll find a huge amount of American material about that. I’m not going to touch it, this whole post is about the UK Government report on the potential threats from space weather, published in July of this year.

And I’m suggesting that it’s very possible to construct a Faraday Cage from the simplest materials. A couple of nested cardboard boxes. Heavy duty aluminium foil. The boxes are free at many supermarkets, or you can buy them at a poundstore or a stationer’s. It makes sense to buy the heavy duty foil: this one had a lot of customers recommending it.    Some of the products on Amazon have even better reviews.   

And there’s aluminium tape too, to make sure the edges don’t undermine the integrity of the insulation, though it seems you can get away with folding over (at least twice) the foil edges that you want to join.

So, here are the steps:

  • get two cardboard boxes, sized so that one will fit inside the other.
  • check that all the goods you want to protect will fit inside, even when they’re wrapped up in another few layers of insulating material and foil.
  • wrap the body of the box in a couple of layers of foil. Pay particular attention to where the foil edges meet one another: fold the edges over, and/or use that aluminium tape on them, if you can.
  • it’s really important that the foil doesn’t tear: that’s why I’m suggesting nesting cardboard boxes. The outer box is only for the protection of the inner box, which is the one covered in aluminium foil.
  • I recommend each item be wrapped in an insulating layer, a foil layer, another insulating layer, another foil layer. Sheets of bubble wrap and the like are fine.
  • don’t overfill, you need to be sure that you can tape down the lid very, very snugly. FCs only succeed if the gaps in them are substantially smaller than the wavelength of the solar radiation involved. And, as wiki sums up so admirably, radio frequencies go down to 0.1mm,though to be fair these have the attractive name of “Tremendously High Frequency”. Very little of this radiation usually gets down to ground surface, but in a big geomagnetic storm, some might. Reason enough to make sure you seal the box carefully.

That’s it!  Warnings of space weather severe enough to do damage would be all over the media. You could also check space weather warnings daily here,  and that would mean you don’t even need to have your FC sealed up, especially bearing in mind that there’s a fairly low probability of a severe geomagnetic storm in any one year. Sooner or later, random chance means that it will happen, of course – maybe many years from now, maybe tomorrow.

So, given how easy it is to provide a prepper-level protection against geomagnetic storms (as opposed to a scientific lab with equipment worth millions of pounds) I recommend keeping the makings of a Faraday Cage handily available – in the loft would be good enough. Two cardboard boxes, a couple of rolls of supermarket level heavy duty foil, and maybe a roll of aluminium tape, plus insulating material, such as pillow cases, used bubble wrap, anything non-conductive. Along with keeping an ear out for space weather forecasts, the same as checking for forecasts of extreme heat/cold/rain etc.

I hope this is helpful!


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