Reversing The Polarity – are magnets a risk to safety in the mountains?

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If you’re venturing into the wilds and going to be doing some proper map reading and using a compass (or might need to do so to rescue yourself), then Mountaineering Scotland has issued a press release which warns you to pay attention to what you’re wearing.

Apparently magnets may not be such a great substitute for pocket closures – and certainly we’ve seen a few items of mountain bike clothing where magnets are used for closures, to stop hoods flapping, or to keep your hydration hose in place. Why? Because you might inadvertently reverse the polarity on your compass. It might sound cool, but it won’t launch you into hyperspace – and could send you in completely the wrong direction.

To be fair, riders at trails centres are unlikely to need a compass, and even riding local natural trails you’re rarely in need of a compass – except perhaps in disorientating fog or snow. And if we’re being honest, how many of us actually have a compass in our packs?

Where do we go from here?

However, it’s still worth bearing in mind where you keep your compass, because if you do find you need it, you’ll want it to be working. Read the full press release for a cautionary tale:

Mountain safety experts have warned against a worrying trend in the outdoor clothing market.

Magnetic closures on gloves and jackets are being marketed as the modern alternative to Velcro or poppers.

Magnets are well-known for deflecting compass needles, and there is already evidence that this may have been the cause of a recent Mountain Rescue call-out.

Heather Morning, Mountain Safety Adviser for Mountaineering Scotland, said: “We have reviewed the circumstances of a recent incident in the mountains east of Glen Shee, which involved hundreds of hours of rescue personnel hours and police time.

“A group of walkers were caught in low cloud and headed east instead of west, becoming totally disorientated and ending miles away from a road. Fortunately no-one was hurt – just pride dented – but it could have turned out so much worse had mountain conditions been more severe.

“The reason for the error was the compass. It had been stored in a pocket next to a mobile phone in a case which had a magnetic closure on it, and the magnet had reversed the polarity of the compass needle, so that the north arrow pointed south.”

maglock mountain bike pedals magnet flat pins
Maybe don’t put your compass near these!

This phenomenon of ‘reversed polarity’ has been widely publicised in mountaineering circles and people are advised to keep their compasses well away from mobile phones. But there is concern at the growing use of magnetic closures in outdoor clothing. Popular outdoor brands are producing mitts/gloves with fold-back flaps using magnetic closures and there is a wide choice of outdoor jackets out there replacing Velcro with magnets hidden away in folds of the garment. Pockets, hoods, front fastenings, wrist closures… they’re all out there.

Heather warned: “Modern technology is great. The resources available now to keep us warm and safe in the mountains have never been better. But more joined-up thinking is needed between outdoor clothing manufacturers and mountain users to avoid potentially life-threatening consequences.

“My advice is to steer well clear of any garments utilizing this latest trend of magnetic closures or you could end up with an expensive bill for replacing your compass or – worse – a life-threatening navigation error.”

Comments (7)

  1. GPS units either use an actual magnetic compass or more commonly a differential compass. The differential compass only works if you are moving, so it’s still not fool proof.

  2. GPS also requires batteries!

  3. I managed to reverse the polarity of a compass many years ago by leaving it next to my camera in the pack. I realised so came to no harm, but I’ve been very careful where to keep the compass ever since, and it gets harder the more electronic stuff we carry about. Having magnets sewn into your clothing seems a really bad idea if there’s any chance you’ll be using a compass. Makes you wonder just how ‘outdoor’ the ‘outdoor’ brand designers really are.

  4. To anyone from the Outdoor Clothing industry:-

    Magnets are not a ‘worrying trend’. Those new zip pulls which accurately snap into place so zips can be fastened one handed are the best feature you can add to jackets and gillets. Thanks.

  5. To anyone from the Outdoor Clothing and Equipment Industry (and I used to be one) – Magnets in clothing and kit ARE a worrying new trend. The brand I worked for dismissed the idea years ago, precisely because of the issue with compasses. Getting lost is pretty inconvenient. It’s pretty inconvenient for members of Mountain Rescue Teams to drop what they are doing to go and look for someone.

  6. Yeah, well anyone using a compass rather than a phone for navigation is probably pretty clued up.

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