How Your Avalanche Beacon Can Kill

Post by blogger | May 1, 2019      

This post sponsored by our publishing partner Cripple Creek Backcountry.

I’ve been intending to post this up… finally got to it. Info for folks new to avalanche beacons and companion rescue. And fodder for discussion.

Throughout my years of beacon practice drills that involve an actual rescue simulation, one thing has stood out: Involve more than a few people, Mr. Chaos will pay a visit. And a big contributor to the melee will probably be non-victim beacons that remain transmitting (or are accidentally switched to transmit), or have an automatic revert-to-transmit (AR) mode that kicks in at the worst moment. The latter, AR, is what this blog post is about, but we’ll touch on the other issues as well. (Accidental switching is a very real problem.)

Let’s call this the “Third Law of AR.” Definition: In an avalanche beacon search involving more than a handful of experienced and immediate companions, confusion will grow with the number of searchers like an exponentially blooming bacterial soup, often due at least in part to AR, (and perhaps due to poorly designed mode switches that too-easily trip over to transmit mode, not a subject of this post).

A moment with Goog The Great brought me to the Pieps website, and a good list of ideas and concerns about AR. Paraphrased below, with a few extra from me.

1. Pieps is of the opinion that AR is for pros only, apparently it’s disabled by default.

2. The easiest to imagine negative scenario is that of a beacon in search mode being lost during a search. If AR is enabled, on it goes and confusion commences. It’s not far fetched to figure beacons can be lost, or placed aside by under-trained individuals in the heat of battle. (And don’t depend on transceiver leashes, the CE standard requires them to hold up to five kilos, no more.)

3. If the rare event happens and a searcher depending on AR gets buried, spotters outside the avalanche area must wait for the timeout to begin searching. Sometimes eight minutes! (Thus, with the current state of beacons, perhaps it’s best to just keep your fingers on the transmit switch if you do feel under threat, and even then, you’re going to depend on the lanyard to prevent the white cyclone from taking your beacon? Sounds far fetched — typical untested theory of avalanche safety, actually. More, let’s keep in mind it’s rare to do a real-life beacon search under threat of secondary avalanches. Sure, could happen, but so could rockfall, or a lightening strike, or falling aircraft. So, to be clear, I’d simply prefer all beacons physically locked in search mode, and had AR disabled by default.)

4. Rescuers and bystanders, especially those inexperienced, may deliberately set their beacon aside and forget about it.

5. If AR is enabled, it often triggers with a loud and confusing warning signal. Confusion already rules, do you need more?

6. Sinners will sin and everyone is a sinner… it’s not uncommon for skiers to carry their beacon in their backpack, especially when they feel they’re at no risk of slides. Set your backpack down, leave it, invoke AR.

7. Untrained individuals may not even know what the AR warning is. And they’ll definitly not know how to turn it off.

8. Yes Virginia, most beacons have a “marking” or other type of function you can use to cut unwanted signals. Nice when needed, isn’t easy to use for moving, disappearing reappearing signals,takes extra time, and often requires training not everyone has the time or motivation for. More, it’s horribly confusing when you’re homing in on a search, then bam, an AR signal comes in when you think you’ve got things handled.

So, in my opinion, sport a beacon with AR disabled. Enable it if you feel you need it during a specific search, or just keep your finger on the trigger.

From what I could gather, here is the state of AR you’ll get if you buy a new rig in a few representative models. Whatever you buy, check the specs, and be sure AR is default disabled, or easily user disabled. And if you like AR, do dagger eyes my way and enable.

BCA Tracker 3
Disabled by default. If you want AR, you enable it each time you power up. In my view, it sounds like AR in the case of Tracker is something you’d _rarely_ want to enable. (By the way, note the Tracker mode switch does not lock in search mode and is in my opinion easily bumped or otherwise accidentally switched to transmit mode. This is not a unique issue, other brand/models may present that way.)

Here is how BCA specs it out. Again, sounds like something you’d pretty much not want:
“Auto revert mode will make your Tracker3 automatically revert to TR (transmit) mode if the device does not move for one minute — or if there is movement, but the searcher remains in search mode for more than five minutes. An alarm will sound 30 seconds before the unit returns to transmit mode. This can be avoided by pressing the Options button or turning the dial switch before the 30-second warning period has elapsed.”

Same with Barryvox. The following indicates you’d only want AR enabled for truly bad situations. Official word:
“1) The auto-revert needs 50-seconds of motion to stop the timer. This means if the auto-revert is set to 4 minutes, that 3:10 of no motion is the “point of no return,” after which it will revert regardless of motion.
2) Barryvox auto-revert is the default, though it can be disabled in the setup. [Bummer]
3) Auto revert time can be set to either 4 min or 2 min.”

Pieps & Black Diamond
The Pieps and Black Diamond, BT & Powder (and equivalent BD models) have AR disabled by default. It can be enabled via a Bluetooth connection and app. Once enabled, the AR is based on the now ubiquitous time/motion algo. It’s said the Pieps AR acts with a “short switching timeout with a long warning phase.” Sounds like all the more reason to forget it.

(Note regarding Pieps/BD rigs with the slider switch: As with BCA, it’s probably by design that the switch does _not_ lock in search mode, thus allowing you to slide it back to send mode in the event of a secondary avalanche. Thing is, if you handle the beacon roughly it’s theoretically possible to accidentally slide the switch to transmit. Knowing your rig, and training with it, should obviate any possibility of accidental switching, as the slider on current BD/Pieps models is adequately stiff. If you have an older vintage, check your slider switch, I’ve heard of some that move perhaps too easily.)

We recently reviewed that new, sweet, little Evo5. Unfortunately, this guy comes with default AR of eight minutes, no movement. Apparently the time buffer can be increased, or AR disabled — but doing so requires some kind of settings input we could not get clear on. As stated in the review, we’ll revisit that when I get more information. I inferred from the skeletal info on the Arva site that their other rigs are similar. Happy to be corrected. (Again, slider switch does not lock in search mode and slides easily into transmit.)

Whatever beacon you own, do determine its AR flavor, and disable unless you feel an over-arching need. Test AR by setting the beacon on your desk, in receive mode, and see what happens. Then test with the beacon in your pocket, while walking around. Also test the switch, so you’ll at least know how easy it is to accidentally bump from search mode to transmit (again, most move too easily in my opinion).

There you go, beware the Third Law of AR!

(I’m not sure what’s appropriate for institutional situations, such as a guide passing out beacons to day clients. Any guides have a comment? Do you keep auto-revert enabled for all your clients? Disable? Don’t pay attention to it?)


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28 Responses to “How Your Avalanche Beacon Can Kill”

  1. VT skier May 1st, 2019 3:36 pm

    I just tested my Ortovox 3+ beacon for AR , or ” Auto Revert to Transmit Mode”.

    With the latest software upgrade to V2.2, performed by Ortovox in Germany, the beacon switched to AR mode after 2 minutes of inactivity. It gave out 10 seconds of beeps, before this happened.

    While skiing in France, with some friends, in April I gave this spare beacon to a friend to wear, when we were skiing off piste (close to groomed runs) . After a quick description of how it works, ( and I might add, he had no avy training), we headed off. I told him, if he comes to a site where searchers are working, probing for a buried skier, to
    Turn Off His Beacon !

  2. swissiphic May 2nd, 2019 9:17 am

    Lou; I agree with your sentiments regarding A.R.

    Curious, do you have stats on the percentage of real world scenarios where rescuers were overcome/buried by a secondary avalanche during a search for buried victims?

  3. swissiphic May 2nd, 2019 9:19 am

    …twould be nice to get some context for the issue.

  4. Rick May 2nd, 2019 10:16 am

    “Sinners will sin and everyone is a sinner… it’s not uncommon for skiers to carry their beacon in their backpack, especially when they feel they’re at no risk of slides. Set the backpack down, invoke AR.”

    Is this to say that folks commonly turn their transceiver to search mode, toss it in a pack, and proceed on their way?

    I have zero data to rely upon, however I suspect that most folks who ‘sin’ as above are doing so with a transceiver in transmit mode.

    Auto-revert doesn’t apply in transmit mode; your scenario above seems unlikely.

  5. Lou Dawson 2 May 2nd, 2019 10:24 am

    Swiss, I’ve studied the North American literature like I was preparing for a bar exam, and I can’t recall a single instance of a secondary avalanche requiring a companion rescue, proximate to an original rescue. There are probably a few instances buried in there, but so few as to be statistically insignificant. I think the chances of AR taking a life rather then saving it are so serious in comparison as to make the whole AR thing look like some kind of “featuritis” symptomatic of bored electronics engineers or more likely, companies competing for bells and whistles, or, is it required by CE standards? If so, ignore half the above diatribe (smile), and apologies to engineers.

    To be fair, I’d bet there are more instances of secondary avalanches on rescues in Europe, if for no other reason than the shear volume of avalanche rescues over there. But I’ll bet if you parsed it out statistically, they still be insignificant compared to the need for ease-of-use and reduced confusion.

    If someone comes up with an example of a secondary burial during a rescue, I’d say that’s a pretty good example of the exception that proves the rule. Rule being it’s rare as hen’s teeth.

  6. Fabrizio May 2nd, 2019 11:02 am

    One case in switzerland comes to mind:
    2010, Diemtigtal: primary avalanche buries a backcountry skier. Rescuers are flown in by heli. Secondary avalanche buries and kills 7 people, including one ER doctor from the rescue team.
    According to the avalanche report, the person buried by the fist avalanche was found quickly (alive). People at the avalanche site were instructed to switch off their beacons to facilitate a safety search to make sure no one else was buried. Then, multiple secondary avalanches hit and buried 12 people, 7 of which died.
    More details on PDF found on
    (page 55, in german)
    This accident report states that one of the biggest issues leading to the fatalities was that all beacons were either switched off or in send mode.

  7. John B May 2nd, 2019 11:05 am

    Thanks for the post Lou. It seems like the entire avalanche world is focused upon consequences vs likelyhood. It seems like situations where AR is necessary are such a low likelyhood that it’s more likely to create further confusion and delay as opposed to saving a life.

    As said in your last paragraph I’d be curious what large guided companies choose to do.

  8. Kristian May 2nd, 2019 11:16 am

    I am guessing that AR could be useful for those doing a beacon check of others or a practice search and then forgetting to switch back to transmit later.

    Would be nice to have very obvious stupid simple 3 universal color coded unique shaped symbols common to all beacons. Something like:

    Round Red Off
    Square Green Transmit
    Yellow Triangle Search.

  9. Kristian May 2nd, 2019 11:25 am

    The color coded symbols would face outwards, have a 1 cm diameter, and be seen easily by others. A sliding switch would reveal only one color symbol.

  10. cam May 2nd, 2019 12:01 pm

    Great post!

  11. Gary May 2nd, 2019 12:43 pm

    I have the Barryvox S. A loud beep comes on to warn of auto revert. You push the only button on transiver and remain on search. I have practiced with it which is key. Just know if you and I are skiing together and I am buried by hangfire or secondary avalanche I will be transmitting in 4 miuutes.

  12. Lou Dawson 2 May 3rd, 2019 1:16 pm

    Thanks for the example Fabrizio, super valuable to have that in this thread.

    Makes me think of another point. The first priority of SAR, let’s spell that PRIORITY, is to protect the rescuers, that means PROTECT, not depend on them perhaps being dug out of an avalanche alive, it means evaluating hazard and being careful of exposure to hazards. And, after all that, of course if you did have a rescue happening while underneath a loaded, prime avalanche path, you’d need to invoke AR, or keep that finger on the trigger. But using one, or two, or even three of these sorts of situations to justify a confusing and potentially dangerous feature, that could easily disrupt almost any search, is IMHO illogical.

  13. Scott S Allen May 3rd, 2019 1:21 pm

    Fascinating….brings to light a feature I didn’t know I had on my current device (Ortovox 3+ post recall for software update) and now wish I didn’t have!

  14. Mike May 3rd, 2019 11:46 pm

    This does not change the point of your argument but your information is incorrect here. “The Pieps and Black Diamond, BT & Powder (and equivalent BD models) have AR disabled by default. Only a service center can enable.” Current top models do not require service center for changing of settings.

  15. Lou Dawson 2 May 4th, 2019 8:53 am

    Thanks Mike, I didn’t pull my info out of thin air, but my source must have been off. I’ll double check and edit. Lou

  16. Lou Dawson 2 May 4th, 2019 9:05 am

    Looks like where I got confused is the “BT” Bluetooth badge on the front of the Recon beacon is almost invisible. Thanks for the help. The AR of the BD Recon/ Pieps is disabled by default, and user configured using a Bluetooth connected app. I’ll be sure my diatribe about AR doesn’t mislead on this. Lou

    From the BD/Pieps beacon manual:
    4.7.1 Secondary avalanche | Auto-Search-to-Send
    The BLACK DIAMOND GUIDE BT/RECON BT provides the feature Auto-Search-to-Send. By default, it is disabled
    and can be enabled in the PIEPS APP device manager. Once enabled, the device switches from search mode to
    send mode automatically after a certain time without motion (burial).
    The function provides the following characteristics:
    • Motion-controlled initialization
    • Short switching timeout
    • Long warning phase with alert and countdown prior to switching
    • Continued alert, also after switching

  17. Bard May 4th, 2019 11:00 am

    I agree Lou. Some people who demand the most feature-laden beacons are the same folks who would benefit from an idiot proof unit. Everyone is an expert until the s—- hits the fan. The range and battery life of today’s beacons is impressive, but let’s not get overwhelmed by too many bells and whistles. Keep it simple.

  18. See May 4th, 2019 8:46 pm

    I know we’re supposed to keep our phones away from our beacons, but with bluetooth beacon apps, and headphones and inreaches, etc., I wonder what is best practice regarding radio interference.

  19. Lou Dawson 2 May 5th, 2019 7:59 am

    See, the RFI issue tends to be exaggerated, as it often is in many walks of life (oh my God, those power lines are a mile away, too close!!). RFI is all about specific frequencies, strength of signal, and proximity to source. There is no way to know how each RFI source interacts with each device, other than specific real-world testing. Which the user can do. Rubber band your phone to your beacon and see what happens. Then try it with you phone in your pocket and your beacon in the other pocket… and so forth. I did a lot of experimenting once and I was able to get some results when I attached the phone to the beacon, otherwise I saw nothing.

    As you probably know but is worth repeating, the entire universe is jam packed with RFI. Electronic devices themselves are packed with it, internally. It’s literally more ubiquitous than the air we breath.


  20. Mike May 5th, 2019 12:01 pm

    If your Transceiver (“Beacon” by definition is only signal emitting capability, not receiving. It is the “forward pressure” misnomer of the avalanche safety world) has an analog mode, the Pieps BT and Mammut products do, just switch to analog and listen for the interference from your other electronic devices. Its very easy to hear the static sounding interference cover over the beeps from the other transceivers still in send mode. I’ve played around with my phone in close proximity to my transceiver and its very noticeable. When in digital mode the poor computer is having to deal with all that interference and still try and keep potentially many signals, all on the same frequency, separated to allow marking and other advanced functions to work. I have not checked my radio to see what effect it has.

  21. See May 5th, 2019 6:45 pm

    Those electronic devices packed with RFI are also often packed with shielding. I don’t wear an aluminum foil hat, but I admit that I prefer to talk on my cell phone using earbuds rather than hold the thing up against my head.
    Just like I cut the labels off my gear to save weight, I think I’ll continue to keep some separation between my transceiver and my cell phone. It may only make a tiny, maybe trivial difference, but it makes a difference. Thanks for the responses.

  22. joseph May 6th, 2019 8:23 am

    Pieps has a backup transmitter. I bought this for my daughter when she was 5 and couldn’t operate a beacon herself anyway (it’s not meant for this, but it does work in companion with another beacon only if you know what you’re doing).

    But I now wear it myself in my pants pocket and keep my beacon in my backpack. Three reasons: 1. it’s smaller and lighter and I hate my Barryvox harness. 2. If my backpack gets torn off in an avalanche I have something on me that switches to send after a while. 3. I no longer have to use AR. This is actually the intended use for the device.

  23. Rolf May 7th, 2019 4:33 am

    In trying to avoid potential confusion in rescues, carrying a transceiver in your backpack and having a back-up transceiver in your pocket, doesn’t feel like the best solution. If the backpack gets torn off, you will end up with 2 signals for 1 victim and 1 of them will even be useless (the backpack).

    As for RFI many international organisations (UIAGM, ICAR, UIAA, etc.) are adopting the following rules:
    Transceiver in SENT mode: min 20 cm distance between source (turned ON) and transceiver
    Transceiver in RECEIVE mode: min 50 cm between source (but turned OFF!!) and transceiver
    Sources turned ON (exemple: someone calling for help) should be 25 m away from anyone searching.

  24. See May 7th, 2019 7:49 am

    With all the electronic devices people carry these days (gps, action cam, satellite communicator, wireless headphones, sport watch, etc.), I’m reminded of a weird thing I observed with a car dash cam a while ago. RFI from the camera totally disabled the car’s remote door locks.

  25. Rolf May 8th, 2019 2:11 am

    “So, in my opinion, sport a beacon with AR disabled. Enable it if you feel you need it during a specific search, or just keep your finger on the trigger.”

    The ‘keeping your finger on the trigger’ advice suggests it should be easy to switch from search to send (you won’t have too much time I guess). In the review of the ARVA EVO 5 you noted it is to easy to switch back to sent (too little force is needed).

    This is an interesting discussion: how easy should it be to switch from search to send? How much force is reasonable? Or how easy should it be ergonomically? And when is it too easy (ARVA EVO models, old PIEPS DSP which slider wears a lot)?

    Can we sort this out, or should these issues just be personal preferences?

  26. Lou Dawson 2 May 8th, 2019 7:09 am

    Hi Rolf, I meant to suggest no such thing, I’m only dealing with reality, and that’s that most beacons are easy to switch from search to send. So in that case, keeping finger on the trigger is quite effective and should be mentioned. In my opinion, the beacon should lock in search mode, but have some kind of integrated button/lock, and an optional setting to enable AR, for those 3 times a year someone on the entire planet has do do a beacon search under hangfire. I’ll do a bit of editing to resolve conflict in the writing. Thanks for pointing it out. Lou

  27. Lou Dawson 2 May 8th, 2019 7:25 am

    Guidelines and awareness of RFI (aka EMI) is all well and good. But let’s keep in mind that the root cause of the problem is the weak signal beacons transmit. The meager signal is necessary to preserve batteries, but what if it was even 10% stronger? That could very well eliminate most of the issues with RFI. (Study up on RFI, it’s all about the ratio of desired signal over ambient or otherwise undesired electronic noise, which becomes RFI when it interferes.)

    Interesting how a device (beacon) that’s been around for about a half a century could be so fraught, eh? Amusing until it costs a life.

  28. Rolf May 8th, 2019 8:05 am

    Thnx for your reply Lou! I agree that beacons should lock in search mode and I am, as you are, not very concerned about rescues under hangfire.

    As for RFI: transceiver transmit power is a a given for the moment. So guidelines and awareness might be handy.

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