I didn't realize AMK had this product out, but was checking out their site and saw it. I love the heatsheets and emergency bivvy, so I'm curious about this one.

Has anyone heard anything good/bad about it yet? In this price range I wonder how it compares to a blizzard bag or a dedicated sleeping bag like the snugpack jungle bag or sleeper light.

http://www.adventuremedicalkits.com/product.php?product=263&catname=Shelter&prodname=Escape%20Bivvy%20-%20Shipping%20January%202012!#

Izzy mentioned a few weeks ago that this was coming but I haven't seen it in the stores around here yet. I picked up a new emergency bivvy at Sail yesterday and they haven't got it yet.

just came out this month. been awaiting reviews too.

It would be nice if they provided some sort of temperature rating. It looks like an interesting product.

Trouble is - these aren't sleeping bags. They're emergency items where you put on all your clothing and creep into your own micro-climate away from the wind, rain and snow.

They're not insulated, and a sleeping bag type temperature rating will be very un-impressive, to say the least.

Bivy bags and sleeping bags are totally different products - the only similarity is that you can (try to) sleep in both.

By "try to," what exactly do you mean? I have been in sleeping bags, some are better than others, but I have yet to sleep in a bivy.

Jeanette Isabelle

True enough, but their web site description includes the phrase "equivalent to a medium-size sleeping bag" which strongly implies some insulation value. Their illustration shows interior baffling which should provide some insulation. At $50, they are priced within the range of some fairly cheap and reasonably warm sleeping bags, like the Slumberjack brand. it will be interesting to see the results of objective valuations, like those often provided by ETS.

Right now, I am not sure I would run right out and buy one. If bulk and weight (such as something carried in a car) were not a consideration, I would go with an inexpensive, synthetic fill bag for roughly the same price.

If this product does provide some insulation value above and beyond that provided by other AMK bivvy products, it might be worth it.

To try and answer JI's question, you can sleep just fine in a bivvy sack, provided you are significantly exercised. Sleeping in a nice, cozy, warm sleeping bag can be as good as it gets.

The first application of bivvy sacks was for alpinists caught out overnight by a storm or darkness or both. They were designed as a minimal shelter to keep rain and snow away from clothing. Typically the user would not even be lying down, but would be sitting on a ledge, often tied in to prevent a fall. They were successful if you could see dawn the next morning, and recognize it as such.

The insulating value was nil. The makers of the current mylar varieties rave on about their reflective qualities which only applies to their ability to reflect radiant heat. That unfortunately is irrelevant, since the vast majority of heat flow in the typical outdoors setting is by conduction or convection (sitting on cold ground or in a breeze).

Bivys have "evolved," so that some now are basically very small (and expensive) tents. Still all they supply is a shield against the environment; the sleeping bag or clothing gives insulation

By "try to" I meant that you might TRY to sleep in a bivy - but most likely you'll find it difficult to get your golden dose of eight hours of uninterupted sleep and sweet dreams.

Bivys are clammy (vapor barrier) and uninsulated = cold.

When you really, really need them bivy's are worth their weight in gold. By sealing all that vapor inside the bivy you eliminate heat loss from evaporation. Yes, it's clammy, but that's a HUGE heat loss factor that you've eliminated. You also are completely sheltered from wind, rain, sleet and snow. Even though they're uninsulated (= cold) the micro climate inside is MUCH warmer than on the outside. The price you pay is that it's clammy and claustrophobic.

As always, your mileage will vary considerably. Some will sleep through whatever, no matter how clammy. Others have trouble in a regular sleeping bag - not because they're uncomfortable but because it is totally different from their reguar bed.

Face it - if bivy's were comfortable NO ONE would mess around with tents and sleeping bags.

In my opinion the shelter aspect is by far the biggest value of a bivy. If you are wearing reasonably adequate clothing and can improvise some insulation from the ground underneath you (a foam pad, for example), with a bivy you can make it through the night. You may not sleep much, but you will survive.