Emergency bivy protocol

21 Aug 2013 10:45 #58147 by ghaznavid
A topic I have been thinking about a lot recently is the protocol for an emergency bivy without a sleeping bag.

Has anyone out there ever had to do a space blanket bivy? I would be interested to hear what you ended up having to do, tips etc. I imagine the adventure racers out there would be experienced in this?

My understanding is that you find a sheltered spot - overhangs are great, but otherwise somewhere out of the wind/rain (if possible). Unlike a sleeping bag you would go for as much clothing as possible (although I'm not sure on this), and you would use rocks to hold the space blanket closed. Naturally you can't put your head into the setup, so you would have to wear a beanie/buff/balaclava. You would need to keep a degree of airflow through the bivy to avoid being too wet in the morning - but I imagine that any variation of a space blanket bivy would result in waking up in a wet state.

If you were wet when you had to bivy (maybe you got caught in a thunderstorm), would you keep your wet clothes on seeing as inside a space blanket your wet clothes shouldn't make you cold.

I'm also wondering if it isn't worth doing a practice run on this, maybe near Giant's Castle or Garden Castle carpark - go with the gear I would carry on a day hike and have all the emergency stuff sitting in my car (just in case it goes badly). Wouldn't try this in winter though.
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21 Aug 2013 11:59 #58149 by Selous
Replied by Selous on topic Emergency bivy protocol
Nice topic Ghaz

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21 Aug 2013 12:19 #58150 by tiska
Replied by tiska on topic Emergency bivy protocol
I would think the best way to get a space blanket to work would be to tape it round you using something like (but lighter than) gaffer tape. Heat gets lost through convection, conduction and radiation. The space blanket will reduce some of the radiative loss because it is reflective. It will reduce some of the convective loss if you can wrap it tightly around you. But even a small hole or gap which lets cold air in will drastically increase the heat loss.

Keeping wet clothes on will also steal heat from you. Clothes will be warmed by body heat and the warmer the clothes, the higher the evaporative loss from the clothes. With the evaporative loss there will be a latent heat tax on your system. Basically your body heat pays for the conversion of the water from liquid to gas. Wet clothes therefore keep you cool. My approach to dealing with these kinds of situations is to keep the wet clothes on while you are walking (and generating a lot of heat) and change to dry clothes as soon as you can get out of the rain. The approach requires you to be fit enough to keep going until you reach a dry place and assumes you are not injured and can walk.
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21 Aug 2013 12:40 #58151 by ghaznavid
Replied by ghaznavid on topic Emergency bivy protocol
Thanks Tiska, that makes sense. Just thinking practically - maybe not a bad idea to start carrying general tape in my first aid kit.

Scenario:
A person and a friend are doing an epic day hike, they hit the escarpment and a massive snow storm strikes, somebody falls and breaks their leg and its too far so a trekking pole splint and crutch setup won't help. Mountain rescue can't come till the storm blows over so the team is facing at least a 1 night bivy and is equipped with only the usual stuff you take on a day hike:
- The clothes you have on, but they are all wet
- Your raincoat, fleece top, gloves and beanie
- A towel
- Normal stuff not relevant to the topic - a headlamp, map, a short light rope, food and water
- First aid kit that includes plasters, elastoplast tape and a space blanket each

So you would use the first aid kit to patch up the person, use a badage and dismantled trekking pole for a splint. You would then scout around for a suitable bivy spot, help them to the spot, get them out of their wet clothes, a towel will come in handy here and then get any dry clothes they have onto them, then you would wrap them tightly in a space blanket and use tape (or plasters if you had nothing else) to close the space blanket up. You would phone mountain rescue and then you would wrap yourself up. If hypothermia became a risk you would have to unwrap both yourself and them and wrap the space blanket around both of you - much like the Messner brothers' bivy on Nanga Parbat at 8000m (RM estimated the temperature hit -30).

Do you agree?

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21 Aug 2013 12:49 #58152 by DeonS
Replied by DeonS on topic Emergency bivy protocol
From experience in my day’s off playing soldiers – bad idea to wrap it around your sleeping bag because of the condensation on the inside of it causing the sleeping bag to get wet, the warm moisture fools you in thinking you are warm till you take the blanket off. Found it worked better sitting up wrapped around your body and allowing moisture to escape from around your neck and head. Wearing something warm on your head keeps that warm.
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21 Aug 2013 13:43 #58155 by kbresler
Replied by kbresler on topic Emergency bivy protocol
Interesting topic!!

You should always have some sort of tape in your med kit or wrapped around a trekking pole of water bottle. The stuff is just useful. Plaster roll also works well for certain applications. I guess avoid getting to the escarpment without a sleeping bag is first prize. But otherwise in my personal experience what Deon mentioned makes the most sense. Either way you are in for a crappy night. Condensation is dangerous and some form of ventilation will be important.

One of the most important aspects of mountain travel seems to be overlooked though. Why are you wet in the first place? Where is your rain jacket?

Kobus Bresler

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21 Aug 2013 13:51 #58157 by ghaznavid
Replied by ghaznavid on topic Emergency bivy protocol
You could be wet from falling in a river :pinch:

I've been on the escarpment without a sleeping bag a few times - in places like Giant's Castle where you can almost always hit the car park within 6 hours, day hiking without a sleeping bag should be relatively safe. But hypothetically, another scenario is that you fell in a river and despite wrapping your sleeping bag in packets it somehow got soaked. Or maybe your backpack rolled down the mountain and fell off a cliff when you sat down for a break - this almost happened to me on Gypaetus Pass.
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21 Aug 2013 15:04 #58161 by Stijn
Replied by Stijn on topic Emergency bivy protocol

ghaznavid wrote: You could be wet from falling in a river :pinch:

I've been on the escarpment without a sleeping bag a few times - in places like Giant's Castle where you can almost always hit the car park within 6 hours, day hiking without a sleeping bag should be relatively safe. But hypothetically, another scenario is that you fell in a river and despite wrapping your sleeping bag in packets it somehow got soaked. Or maybe your backpack rolled down the mountain and fell off a cliff when you sat down for a break - this almost happened to me on Gypaetus Pass.


I've been to the escarpment before without a sleeping bag, but I would always recommend taking some kind of bivvy bag, even if it's those large plastic survival bags that outdoor stores sell. If it's busy pouring/snowing in your scenario above, a space blanket is going to be pretty ineffective on its own IMO. A space blanket inside a survival bag would be much more effective as it doesn't have to keep you dry as well.
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21 Aug 2013 15:20 #58162 by ghaznavid
Replied by ghaznavid on topic Emergency bivy protocol

Stijn wrote: I've been to the escarpment before without a sleeping bag, but I would always recommend taking some kind of bivvy bag, even if it's those large plastic survival bags that outdoor stores sell. If it's busy pouring/snowing in your scenario above, a space blanket is going to be pretty ineffective on its own IMO. A space blanket inside a survival bag would be much more effective as it doesn't have to keep you dry as well.


Ok - maybe I should look at getting one of those.

A space blanket is supposed to be waterproof, so I don't see how water would be an issue, other than maybe coming in by your head. But worst case scenario an emergency bag could be a useful backup/alternative to taping yourself into a space blanket.

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21 Aug 2013 16:00 #58164 by tiska
Replied by tiska on topic Emergency bivy protocol
When two or more things go wrong, the chances of it being your last ever hike are greatly increased. Some of these things, like a big snowstorm, you should be able to anticipate from the weather forecast. You have to be fairly unlucky for three big things to go wrong together- or else make rushed and poor decisions when one or two big things happen and so invent a third big negative all on your own.

I normally take a bivvy bag along and it solves a great range of problems. You can turn a quite wet overhang into something pretty reasonable with one of those. A few times when snow or heavy rain has hit without us having tents, we've just kept on going until we were in shelter. There would have been times when this would not have been possible given who was in the party, but then taking chances with a group that is not fit or particularly strong means that your plans have to be modified to suit the group better - before you set off. Big groups are generally more dangerous in my view.
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