AJ
06-11-2007, 12:02 PM
This is a cross post from the canyons group:
http://groups.yahoo.com/group/canyons/message/37833
Since I'm attempting full Imlay and full Heaps next week, trying to get each of them done in a day (separate days), I just went over a lot of this with my team. However, it might help some others:
I taught many summer and winter survival classes in Michigan; and
people have had many opportunities to test how well (or not) they
worked. As the other person pointed out, you still need insulation
from the cold; especially in full-on snowy winter conditions. The
blanket just does well at reflecting body heat back towards you, and
blocking some of the wind. The bivvy bag style is better at
blocking the wind while you are laying down, but if you are already
hypothermic, less heat is being eminated from your extremities, and
you likely will still need other insulation.
Use your pack, rope, wetsuits, etc for insulation under you. It
helps to have dry clothes with you, you can always use the wet ones
underneath for more insulation, or if it's windy, over you for more
insulation (helps with some of the crinkling.) However, until they
dry, that cold is transferred through the blanket; so use at your
discretion...
For those using the trash bags, in winter conditions, pack them with
leaves or similar for insulation in colder temps.
Another survival trick that works really well is to make a small
fire and hold the space blanket around you and the fire (making sure
your back is to the wind). The heat will be reflected toward you;
and will keep you much warmer with just a small fire. The bivvy bag
styles don't work as well for this.
Another trick is to carry one or two of the handwarmers, and use
them under your arm, around your groin, in the small of your back,
etc. It will help warm the blood transferred to/from your core.
Hope that helps with some ideas. The best thing is to give it a try
and see what works for you... As those have mentioned though, the
space blanket is more of a survival tool than a comfort tool...
Take care,
A.J.
=====
A good link from Ryan:
I thought the following was useful with respect to emergency
blackets... It explains in detail how they work and in what
conditions....
http://www.traditionalmountaineering.org/FAQ_SpaceBlankets.htm
=====
Terry brought up that you could use a fleece sleeping bag; and my thoughts:
Fleece doesn't compress very well. You will get a better warmth to
weight/size ratio using a lightweight down bag. Another good option is just
to use a bivvy sack with a silk sleeping bag liner. That will work
well for moderately warm temperatures (not full on winter unless you
are really warm blooded, and find some good insulating materials to
use under you.) Both the silk liner and bivvy sack will fit in a
stuff sack which is smaller than a nalgene and around 2-3 pounds.
Hope it helps,
A.J.
http://groups.yahoo.com/group/canyons/message/37833
Since I'm attempting full Imlay and full Heaps next week, trying to get each of them done in a day (separate days), I just went over a lot of this with my team. However, it might help some others:
I taught many summer and winter survival classes in Michigan; and
people have had many opportunities to test how well (or not) they
worked. As the other person pointed out, you still need insulation
from the cold; especially in full-on snowy winter conditions. The
blanket just does well at reflecting body heat back towards you, and
blocking some of the wind. The bivvy bag style is better at
blocking the wind while you are laying down, but if you are already
hypothermic, less heat is being eminated from your extremities, and
you likely will still need other insulation.
Use your pack, rope, wetsuits, etc for insulation under you. It
helps to have dry clothes with you, you can always use the wet ones
underneath for more insulation, or if it's windy, over you for more
insulation (helps with some of the crinkling.) However, until they
dry, that cold is transferred through the blanket; so use at your
discretion...
For those using the trash bags, in winter conditions, pack them with
leaves or similar for insulation in colder temps.
Another survival trick that works really well is to make a small
fire and hold the space blanket around you and the fire (making sure
your back is to the wind). The heat will be reflected toward you;
and will keep you much warmer with just a small fire. The bivvy bag
styles don't work as well for this.
Another trick is to carry one or two of the handwarmers, and use
them under your arm, around your groin, in the small of your back,
etc. It will help warm the blood transferred to/from your core.
Hope that helps with some ideas. The best thing is to give it a try
and see what works for you... As those have mentioned though, the
space blanket is more of a survival tool than a comfort tool...
Take care,
A.J.
=====
A good link from Ryan:
I thought the following was useful with respect to emergency
blackets... It explains in detail how they work and in what
conditions....
http://www.traditionalmountaineering.org/FAQ_SpaceBlankets.htm
=====
Terry brought up that you could use a fleece sleeping bag; and my thoughts:
Fleece doesn't compress very well. You will get a better warmth to
weight/size ratio using a lightweight down bag. Another good option is just
to use a bivvy sack with a silk sleeping bag liner. That will work
well for moderately warm temperatures (not full on winter unless you
are really warm blooded, and find some good insulating materials to
use under you.) Both the silk liner and bivvy sack will fit in a
stuff sack which is smaller than a nalgene and around 2-3 pounds.
Hope it helps,
A.J.