Friday, January 29, 2010

Using an Avalanche Beacon to Locate another Beacon

Avalanche Tranceivers and their use.

As I do some research I'm noticing that specific details on avalanche rescue are a little scarce. That may be deliberate as you really need to take a class, and practice practice, practice. I'm going to focus specifically on exactly what I learned and am going to leave a lot of the other detail out.

Tome of basics are listed here:

I think it really needs diagrams but I don't know when I'm going to have time to do them.

The basic gist is that when out on a trip everyone has their tranceiver in transmit mode. If someone is buried then everyone else puts their transceivers in search mode so they can locate the other person.

The methodology in how this happens is really important (such as there needs to be a leader coordinating the whole search.)

The search steps are Primary search for a signal, Secondary search one you find a signal, pinpoint search to locate the victim and dig them out.

The parts we spend the most time on were the secondary search and the pinpoint search. The secondary search happens when you get a signal and you bend down and lower the receiver down to the snow level and start following the arrows on the receiver. Because of the way the radio waves emanate, the approach will naturally be in an arc.

When you're close the numbers (distance away is in meters) will start dropping and the receiver starts beeping more. When you're numbers start to go up again you need to stop and do a pinpoint search. Tell your leader about this - yell!- you will need help with shoveling if that's necessary. For practice searches that are only 1/2 a meter down, it's pretty easy to get numbers down to 0.5 or 0.6, but people buried for real may be buried much further down.

At this point you stop looking at the directional arrows and just look at the numbers. Some people cover them up but I didn't need to.
Now you need to concentrate and focus and that is surprisingly difficult with the ensuing chaos - people often mess this part up, but it's my favorite.
- Note and mark the lowest number that when things were the lowest (say 0.6m)
- Note the place where you noticed the numbers going up and mark that place (say 1.0m - a ski pole is good marker
- back up to past the lowest number and back off to the same amount in the other direction and mark that
- then back to the center and mark the same amount left and right (in this example mark where it hits 1.0 both on the left and right)
- You should now have a search box.

If the number in the marked center is less than a meter then dig with your hands
If more than a meter then the beacon and whatever it is attached to (person, pack or whatever) needs further locating. Assemble your probe and probe the center and work out from the center in a spiral until you get a "strike:" (ouch - the probes are pointed.)
- IMPORTANT, when you have located something, leave the probe in place
- back up about a stride and a half and start digging.
- short strokes are best, stay low and work as fast as you can.
- if it's a person, uncover their face as quick as you can (bummer if the first thing you find is a boot - you can't yank them out as they are likely injured. Keep digging - try not to make it worse but if they live they will likely forgive you for shovel whacks.
- if they are conscious try and have a conversation with them to see if there are other victims (the likelihood of them being at all communicative is not great even if they are alive. Get them medical attention as apparently there's nothing quite like being buried in snow and this is according to first hand reports we were lucky enough to have. One video I saw describe it as like being in concrete.

This all needs to happen with it 15 minutes. The locators on the beacons are so good that when you know what you are doing, you usually can find another beacon with in 3-4 minutes which is good because it takes a while to dig out that much snow if they're 4 feet down (average), which can easily be a ton of snow. This is why calling for help is actually secondary. It's important if they're hurt, but if they are going to live you have to be the one to find them and get them an airway. Such a grim and fascinating topic.

My entire goal of the class was avalanche avoidance, but I must say I liked the search part. It's geocaching with consequences.

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