Best Emergency Shelter? A Bothy Bag

This, again, from mountaineer Andy Kirkpatrick:

BIVVY GEAR: Hugely dependent on the route so here's three examples:

EMERGENCY: Take a bothy bag big enough for everyone and make sure you have a square of foam to sit on. A large metal (MSR, Snow Peak) or alloy pan (Trangia) with a micro gas stove and 100 cartridge, plus a lighter, tin foil lid and windshield is worth taking along on any trip into the mountains as this combined with the bothy can make a grim night even quite pleasurable. Stuff some Cupasoups and Oxos into the pan and stick the whole lot in a bag (it should be pretty light). Make sure you have enough food to last the day and into the night and it's always good to carry something in your 'sack that you know you won't eat unless it's an emergency, like a block of marzipan, Halvah or malt loaf.

SEMI PLANNED: If you're not sure if you'll make it then take more gas (a 200 canister) and some nice food and a bivvy bag and a spare layer to wear inside the bothy bag. Insulated bivvy bags like the Blizzard Bag, or even their Blizzard Jacket (a disposable reflective duvet) may be a great addition to your emergency bivvy kit, as they weigh almost nothing but seriously increase your comfort and protection.

PLANNED BIVVY: If you're hard you can just follow my advice as with the semi planned bivvy, otherwise take along a bigger pan and a cup each if you want to melt more water and hydrate and a light sleeping bag and a _ mat to sleep on and bivvy bag. If you're using a lightweight synthetic you could forego the added weight of a bivvy bag and just use your bothy bag instead.