avalanche probes

[mtngrrrl]

hey there,

i'm looking for opinions on avalanche probes. i like ortovox's equipment in general (i have an ortovox shovel and tranceiver), but i noticed that their probe is on the short side at 2.4 meters. it's also cheaper and lighter, natch. of course i hope i never have to use a probe in dire situations, but i'd hate to have to live with the idea that if i'd only gotten the longer, heavier, more expensive probe, things might be different...

any thoughts on probe length? is 2.4 m on the short side? is 3 meters more than one needs? why 3 meters, anyway?? is there some science behind these measurements?

thanks in advance.

[hikerwa]

I have a 3 meter probe that stashes in my shovel, its a bit heavy, but worth it in the back couuntry. My buddy has a pair of the BD flick lock poles, they're pretty neat in that they can be put togethter to form a probe (i'm not sure what the length is though.) At least that way if you normally have poles then there is no extra weight!

[haireball]

read the literature on avalanche survival. the statistical probability of your recovering someone alive from a burial deeper than two meters is virtually zero. the problem is that even though you may locate a deeply buried person, you can't dig fast enough to save them if they are deeper than about a meter. if you are truly concerned about your ability to save your partner, your choice of gear (probe-poles or dedicated probe; brand of transceiver, etc)is of far less import than the amount of time you are willing to spend practicing with it. professional ski-patrollers at areas with avalanche hazard ratings of class-A (like Stevens Pass, Alpine Meadows, Snowbird)practice pretty much daily with mock burials. unless you are committed to putting in the practice time, it won't matter which probe you're carrying...

[fern]

just as a guideline, the hole you dig to get to a buried person will be about as wide in diameter at the surface as it is deep. Imagine how many meters^3 of compact avy debris you can move in 20minutes, multiply by 12, divide by pi, take a cube root and you'll get the length of probe that might be of actual use to you in an emergency.

[Beck]

Wow, fern, I think you just shot right over the heads of about 90% of your fellow CascadeClimbers... it certaintly dropkicked my melon into the outhouse, that's for sure.

As another practical hint, there's some vector variance in deep burial tranciever searches that generally puts the victims upslope of the point of the strongest signal.

[mtngrrrl]

just to recap, i have an ortovox tranceiver, and i feel very comfortable with it. having tested both the m2 and the tracker, i prefer the m2, no question, but ymmv. yes, i have a shovel as well. and i'm well aware of the virtues of practice, practice, practice, but thanks for the reminder. as far as how much i'm willing to dig, well i would probably keep at it for a LONG time knowing it's my partner's life down there. (this is all rather depressing, isn't it?)

so far it sounds like there isn't a good explanation on the length, which is the real info i'm after here. fern, the mathematician, had some intriguing, if sleep-inducing, answers. i guess it boils down to, longer probe = longer probe-ability.

on a new topic, i've also seen that the avalung has dropped way down in price. it must have been in a recent issue of climbing that i read a pretty favorable review. anyone out there ever tested one of these? it looks like an impressive, easily integrated device, if it works as well as they claim.

well, hey. i just toggled over to visit avalung.com. very cool site, but i also found out that "the statistical average burial depth is about 1 meter."

[Mike]

I assume that you already have a beacon and shovel? And you'd use the probe to retrieve dead bodies - e.g. your friends who didn't have beacons? I definitely want to "second" the advice about practice. "Keep it Simple" is another good motto which is why I bought a DTS tracker - way better than a grid search!

[AJ]

Not to re-open the probe length debate too much, but from my experience there is somewhat of a comfort element to a longer probe. If you are doing a probe search you want to factor in your height. If your hip is approximately 1 meter above the snow then you can assume you will lose that much of the effective probe length because you probably won't stoop over too much in a search. With a 3 meter long probe you would get 2 meters of effective search depth. With a 2.3 meter probe you might only get 1.3 meters.

Oh, part of the cost reduction for the Avalung is the redesign that keeps the size much smaller than in the past. It's effectiveness is reputed to be good if used according to the directions.

[crazy_t]

I have an Ortovox probe; I'm happy with it. It sets up very quickly, and is light and strong. I trust their products in general; they have been the leader in avalanche rescue gear for many years. I believe G3 also makes a good probe, which is graded in centimeters, making it double as a ruler for use in snow stability test pits.

[primate]

Fern:

I think the 12 in your formula should be a 4. If you assume the hole you dig is a cylinder of height h and diameter h, then the horizontal cross-sectional area is pi*(h/2)^2 and the volume of the hole is V=pi*(h/2)^2*h=pi*(h^3)/4. This implies that h=(4V/pi) ^(1/3), so to estimate the depth of a hole from the volume, you would take V, multiply by 4, divide by pi, and take the cube root of the result. This would give you the depth of a cylindrical hole of volume V with height equal to diameter. Perhaps you used a different assumption?

[ 12-07-2001: Message edited by: primate ]

[mtngrrrl]

good point AJ, something i hadn't thought of. being a shortie myself could work out ok with a shorter probe.

thanks to crazy t for weighing in since no one else above seems to have used the ortovox probe.

[primate]

Fern:

I think the 12 in your formula should be a 4. If you assume the hole you dig is a cylinder of height h and diameter h, then the horizontal cross-sectional area is <pi>(h/2)^2 and the volume of the hole is V=<pi>(h/2)^2*h=<pi>(h^3)/4. This implies that h=(4V/<pi&gt ^(1/3), so to estimate the depth of a hole from the volume, you would take V, multiply by 4, divide by pi, and take the cube root of the result. This would give you the depth of a cylindrical hole of volume V with height equal to diameter. Perhaps you used a different assumption?

[fern]

cone with h=2r , but really it was a joke to point out that digging out a deep burial means moving a lot of snow, maybe more than you can hope to move within the narrow time interval that separates a live rescue from a body recovery. If you want to follow my stoopid math you will find that a burial 3m deep requires moving almost twice as much snow as a hole 2.4m deep ... but whatever, it was a dumb joke. As Beck points out ... find buddy with your beacon and start digging the damn hole. IMO a probe isn't an absolute requirement.

for those looking for product review:I have a G3 probe which hasn't had problems yet. However, the writing wears off which makes me think that paying extra for centimeter graduations isn't worth it. And I have been told that the section ends crack after awhile, especially if you assemble it using the chuck-and-pull method rather than assembling it piece by piece.

[Beck]

I carry the Ortovox probe and haven't found any problems with it yet in three years. Take colored electrical tape and mark it in 5cm increments if you want to use it as a snow ruler for snowpit analysis.

 

Is 2.4m too short? Probably not. A beacon search will narrow your search area down by quite a bit, to where probing becomes secondary, quick, prefunctory canine like "find the stick, dig, dig, DIG" when the victim is wearing a transmitting beacon. Probes are probably and unfortunatly used more often in corse/fine search body recoveries.

[allthumbs]

quote:

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Originally posted by Beck:

Do you all go out in the winter with a Texas Instruments Graphing Calculator stuffed in your snow study bag? or Duct taped to the shovel, ready to factor initial diameter for effective penetration at a moment's notice?

Just DIG the DAMN HOLE if your buddies' at the bottom of the pile, I'd save the fancy math for your appointment with the auditor-

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Beck, you're hilarious. You really crack me up. You clever bastard

[Beck]

Do you all go out in the winter with a Texas Instruments Graphing Calculator stuffed in your snow study bag? or Duct taped to the shovel, ready to factor initial diameter for effective penetration at a moment's notice?

Just DIG the DAMN HOLE if your buddies' at the bottom of the pile, I'd save the fancy math for your appointment with the auditor-

[lisa]

I have an Ortovox probe, lite and strong, 240cm. As previous posts mentioned, your probe need not be over 6ft long, the chances of someone surviving such a burial is slim. I also have a BD probe, it's substantialy heavier, but also longer, my error in the first purchase. Ortovox has a great probe on the market that is aluminum w/kevlar cord, it's only 175grams.

Happy turns!