J2Ski Forum Posts and Replies by Nagrjuna

Forcing very short diameter turns works - using your poles more makes it easier to force those little turns.

Another way to handle narrow paths is to simply straightline until speed picks up a bit then snap both skis 180 to the path while keeping your shoulders facing straight down the path, roll onto your uphill edges so as not to catch an edge - skid with your skis at right angles to the path with shoulders facing directly down the path then snap the skis back to normal when you have washed off enough speed - repeat as required. A bit like a rolling hockey stop I guess.

If you don't have the ability to do either of these techniques swallow your pride and bust out the trusty old snowplough? Wanna mix it up? Switch snowplough? :-)

Depends whether you're sliding little short turns or carving longer radius turns.

When bouncing between skidded turns I keep my shoulders more or less squared against the fall line - when carving longer turns my shoulders are a little more squared to my drection of travel (with a slight bias toward the fall line). Quite hard to put it into words what you do with your upper body - it just comes naturally and instinctively - I've never been an instructor so can't really break it down that well!

I think the 'shoulders to the fall line' maxim works best if understood in reverse - there may be points when carving that your shoulders point more toward your direction of travel than straight down the fall line - but you certainly NEVER turn your shoulders up the hill away from the fall line in any circumstances (whether you're skidding turns or carving them) - that route leads to very bad things! If you lose your balance at any point don't give in to the desire to turn your shoulders up the hill to correct a wobble - it won't help matters at all - it throws your body completely out of whack for the next turn.

There is absolutely no need to worry about people being advised to take a course of action that has no possible negative impact, even if you don't beleive there is any positive impact to be had from said course of action. If you switch your phone off needlessly there will be no repercussions whatsoever (in fact you're more likely to have enough battery left to make that emergency call, especially as battery life suffers at cold temperatures) - if you fail to switch off there is some potential for a freak occurance such as when Motorola GP340s was proven to switch the Pieps off or from send mode to search mode.

There is no possible harm, practical or theoretical in telling people to switch off as most manufacturers and many professionals advise - the only possible harm is in telling people to ignore what I consider to be pretty sound advice.

Anyway thats my two cents, from a background as a former Celluar Optimisation Engineer (and a non-pro backcountry skier). But as Ross says everyone has to make their own decisions, hopefully most people will err on the side of safety as really its no skin off anyone's nose to push a button and switch a mobile off however slight the risk may be.

Besides - who on Earth wants a phone call to interrupt a Powder Day, I ski to get away from the hustle and bustle - last thing I'd want is people hangin on the phone hassling me about work!

ise wrote:

Nagrjuna wrote:I'm guessing you're one of those people that simply likes to argue for the sake of it.

.................

If you want to ignore the advice then do so - but as I said don't encourage others to do the same no matter how right you think you are.

No, what I am actually is one of these people who's actually professionally trained and qualified in avalanche safety.

So?

You're still telling people to ignore the advice of other professionals in the industry on the basis of your own views (or your particular training) on the subject!

If you, from your experience, don't want to act on that advice then don't, but don't go round telling others to do the same.

I'm guessing you're one of those people that simply likes to argue for the sake of it. I don't think I posted anything contradictory and don't want to get into an argument about it - I only feel the need to reply because in this case you're actively telling people to disregard part of the safety advise patrollers, manufacturers and trainers routinely include in documentation based on your personal views on the subject. If you don't agree with the standard advice don't follow it - but don't encourage others to do the same!

We wouldn't have to be seeing "lots of incidents" for this to be a potential problem factor. Even if this had been a factor in 90% of burials but only added a few more seconds to search time or required a few more probes to pinopoint a victim we would still not have had the numerous confirmed reports you seem to require before taking a simple cost-free precation. You can't tell whether a rescuer started probing 20cm out because of interference - or whether the directional search was slightly compromised adding a few more vital secnonds to a search. Thats why the beacon manufacturers advise you to switch off, piste patrol searchers do so as a matter of course and many avalanche training courses include the advise when training. They err on the side of safety due to the potential of a problem that could compromise a search however marginally.

If you want to ignore the advice then do so - but as I said don't encourage others to do the same no matter how right you think you are.

ise wrote:
It will remain a hard to dispel story in greater public awareness as these things tend to be.

Why does it need to be dispelled? Whos to say there won't be a problem with furute models of phone or beacon? Do phone manufactures rigourously test every new phone against every beacon on the market? Of course not! Its simply good practice. Every model of mobile that comes on the market is slightly different - whos to say one particualar combination of mobile and beacon won't have a negative interaction. There was a Motorola model a while back that was found to switch a certain Orthovox beacon model from transmit mode to search mode - a potentially fatal interaction between two specific models of beacn/phone.

Its not as if switching your mobile off compromises anything whatsoever - it costs nothing - its there and can be switched on in seconds if you need to make an emergency call. It simply removes a theoretical, if unlikely source of problems in an emergency situation.

So we've established mobiles definately can effect the directional search on a digital multi antanna beacon.

We've also established the transmitting beacon can theoretically be effected in specific circumstances (ie. when the phone is searching for a signal) - though this side of the interference problem is yet to generally accepted and is likely to be of far less impact anyway - the scope of this problem is likely to be around 10-15cm of spike deflection in a worst case scenario - still, a real (or theoretical) possibility of 10-15cm deflection is still a possible negative factor which could mean more probing. So whether its proven or not and however unlikely it is to occur in a real world situtaion its something that can easily be avoided at no cost and no investment of time.

So... for the searcher its proven and for the transmitter its theoretically possible in certain situations. The precaution against both instances costs nothing and takes about two seconds - therefore for me its a total no brainer. Swith the thing off! I really din't see there is any argument - however small the risk involved is, if there is a cost and time free precaution that can be taken, why would you not take that precaution?

I did a test down at the beach a few years back with a digital beacon buried alongside a mobile phone that had no coverage and hadn't aquired a signal. It was impossible to pin down the exact location of the beacon buried with the mobile in the final search as accurately as a beacon buried on its own. It simply wasn't producing the same kind of spike pattern you'd normally expect - if you got that effect in a real life situtation it would lead to having to probe a larger area.

Two things to bear in mind are that ANY source of magnetism/electromagnetism interacts with and diverts the flux lines of a second source of electromagnetic radiation closeby - including the radio waves a beacon puts out. A good way to demonstrate this is to stick a piece of paper to a magnet and sprinkle iron filings on it - you'll get a flux line pattern on the paper - then bring the magnet and paper close to a set of speakers (that have another magnet in them) - you'll clearly see the flux pattern of the original magnet diverted by the effect of the second magnet. This is exactly what can potentiall happen with a mobile near a beacon.

Secondly, the antennae in a beacon are made of ferric material - putting the antennae in a stronger electromagnetic field effects their propeties as transmitting antennae. The ferrile antennae of a beacon are calibrated to work in the electromagnetic field produced by the unit they are part of - change the strength of the field they operate in my factoring in a second source of electromagnetism and its theoretically possible to reduce their effective range. Admittedly this second mechanism is unlikely to have any serious impact - to me its the first mechanism that is the worry.

Theoretically there are clear mechanisms by which a second source of electromagnetism alongside a beacon can negatively effect the ability to find a victim's transmitting beacon. In practice I've seen this effect to some extent and therefore advise people turn their phones off.

A point to note is that modern mobiles only really produce really significant levels of electromagnetism when they can't find the nearest cell antenna and are searching for a signal (something that is far more likely when skiing off piste). As long as you can guarantee you'll be skiing in an area where you mobile gets a signal and won't be searching for the nearest cell you probably won't see any impact on the ability to locate a victims beacon. But in an instance where you're off piste and your mobile is sending out a high strength search signal - there may well be problems.

For me it simply makes sense to remove any additional sources of electromagnetism that have potential for complicating a beacon search. I'm sure everyone has heard the interference from a mobile on a stereo system when it updates with the local cell or recieves a text message - imagine that kind of interference continually confusing a beacon search while a victim's mobile searches for the nearest cell during a search in an area with no network coverage.