warmest lightweight bivy sacks

Looking for a lightweight bivy/sleeping bag/emergency shelter that can go in a pinch if I have to spend an unplanned night out. Its got to be warm, but able to pack down small and be lightweight because otherwise I'll be too tempted to take it out of my bag.

any of these worth checking out?

http://www.backcountrystore.com/stor...-Bivy-Bag.html

http://www.backcountrystore.com/stor...Bivy-Sack.html

http://www.thebackcountry.net/store/...CAMP-EMERGENCY

http://www.mgear.com/pages/product/p...and+Bivy+Sacks

I hear good things about the hot sack, but 80 bucks for whats essentially an emergency blanket? Buy the 12 dollar sucker.

You are packing waaaaay to much stuff man. You dont need a bivy sack for a BC day tour. Extra weight, extra money, whats the point? You'll be doing all of your BC stuff in the Daks and the Whites I'm guessing. At most you'll be a few hours from civilization, you can survive a night digging a snowcave and staying in your emergency blanket if it comes to that. You definately dont need a full on bivy bag for day trips. If you start bringing a bivy bag, then you'll want to have a sleeping bag, and then you'll want a stove, and then....

Also, a bivy bag is designed to keep the weather out, not keep you warm and toasty. That will be a function of what you use in the bivy sack.

thats what I thought about a bivy sack vs an emergency blanket, yeah I know most of my BC is in places close to civilization but the weather in the Dacks and the Whites can change extremely quickly you well know. You can have a nice sunny 30 degree afternoon turn into a very cold -20 night within a matter of a couple of hours. And if its only a matter of a couple of ounces I'd rather bring it. Plus once you get to spring tours with minimal stuff needed in your pack you feel like you're flying

Wut cantdog said.

If you must have an emergency bag, the cheapo aluminum sack is probably the way to go. I have one and have never used it, so I don't know if they work. They're probably better than nothing though.

I don't know what you're carrying in your bag, but rather than bringing lots of layers and an emergency bag you could take a huge puffy down parka instead. A down parka allows you to cut out the multiple synthetics you'd need to get a layering system going; plus you can sleep in the puffy should the shit hit the fan. Bring something light to sweat in on the way up, something to block the wind on the way down, and a puffy jacket for everything else.

Actual bivy sacks don't do much for warmth, but they do cut the wind and keep the water off of you. If you are planning on spending the night out they're one of the lighter shelter options out there. My integral designs bivy (unishelter) has thus far kicked ass.

For an emergency shelter check out the Adventure Medical Bivy. That, a puffy, extra gloves and socks, is what I recomend,

http://akamai.backcountrystore.com.e...um/AMK0002.jpg

I think it was the last issue of Couloir from last season that did a good gear review on bivy sacks. Must get back to work or would search for article...

SuperCow your're really fucking stupid!

I would go with the emergency space banket. Lightwieght and allways in your pack. You don't need a bivy bag unless you want to do min. overnight trips. In a pinch, in the winter, you can make a snow cave or fire. When it comes to survival you can use pine tree bows to make a shelter(living or deadfall). I would make sure I have water proof matches and a fire starter like a magenum bar with flint.

Just my opinion.