I would say one person in a blizzard bag in a bothy bag with 3 friends would be warmest... I don't see a bothy bag as an emergency item, but rather as generally useful kit so you can take breaks out of the wind, which is a very useful thing to be able to do. It not only keeps things warmer but the morale boost inside is tangible.
The blizzard bag, by contrast, is only for emergencies, and emergencies have a habit of removing happy assupmtions like there's a handy place for 4 people to set up a bothy bag conveniently with a casualy too. The one occasion I've attended a rescue in winter was in the wake of an avalanche. Nobody buried, thankfully, but one of the victims had a suspected back injury and, very reasonably was insisting on not going anywhere. He was not in a place or situation where getting him inside a bothy bag would have been at all realistic, and even if it was getting another 3 folk to come and sit in the path of any extra debris would not have been that canny. Bu judicious use of scissors a blizzard bag would have helped keep him warmer with minimal movement. (My snow shovel was very useful that day. When the MRT got there they didn't have any (it was a few years ago, but really...) and ended up pinching mine, so I felt I didn't need to contribute to MRT for a few years after that!)
Not with 3 other people in it it can't! And without anyone else inside it has the insulation value of two sheets of nylon (not much, in other words).
You can place a blizzrd bag on someone too, but say you have a casualty with a broken arm then you can get them in a blizzard bag but cut away at the top to keep the arm from further movement, apply treatment or whatever. You end up cutting up a survival aid. It's just stuff, unlike the person you're trying to help in an environemnt where they will get hypothermia in time.
nevertheless a bothy bag can easily be placed over a casualty with 3 other people (if its a sensible size), or alternatively a bothy bag can be placed over a casualty and 3 other people can crawl inside.
As I said, emergencies have a way of putting paid to nice plans. The actual one I was at a bothy bag would nave been absolutely no use to the two casualties I was helping to look after. They were a few meters apart and neither was up for moving. They were on a moderately steep slope covered in blocks of snow and ice (avalance debris). Being in an avalanche track it would have been follish to have anyone extra there above the minimum.
So as before: a bothy bag is good general purpose kit that can also be useful in emergencies, but a Blizzard bag can make a bigger difference in awkward emergencies. Emergencies cannot be relied upon not to be awkward... There is no reason not to combine blizzard and bothy if you have both. A single blizzard bag amongst a group is pretty trivial extra baggage.
> A single blizzard bag amongst a group is pretty trivial extra baggage.
Well... it depends how many people will need the blizzard bag, and why...
If the entire group is benighted, then only one person in the group can use the bag; most vulnerable/weakest, perhaps? Taking turns, perhaps?
The other reason is injury, and we have to consider the probabilities of the number of casualties involved in an incident. I'd suggest that one casualty is the most common incident. Since an injured person may be suffering from shock, and lying on cold ground, the one carried blizzard bag can be used to keep this one casualty warm, and the healthy members of the group can keep themselves warm by exercise, or in organising the rescue.
Whilst a single blizzard bag won't deal with all eventualities, it may be useful in the most common injury scenario.
Not sure what the most common injury scenario is, but how do you get someone with a broken leg into either a blizzard bag or a survival bag? Isn't the usual advice not to move casualties in case you make their injury worse? In which case a bothy bag is a good move because it can keep both the casualty and an uninjured companion sheltered (conceivably while the companion tears the blizzard bag so that it can be used as a blanket round the casualty). Fwiw I have blizzard bags, survival bags and bothy bags and take whichever selection is appropriate for the trip and conditions. The goal is to be able to survive an injury, benightment or getting lost until rescue. And have a nice time otherwise.
Not sure what the most common injury scenario is, but how do you get someone with a broken leg into either a blizzard bag or a survival bag?
You use scissors or knife to slice it and get it around them as much as reasonably possible before taping it back up. So for a broken leg you'd still have their core wrapped up properly (get it on over their head having chopped the base) and some degree of effectiveness for the leg(s).
Well... it depends how many people will need the blizzard bag, and why...
Quite so. Roos and I carry one each when we're on a ski tour. We used to take one emergency sleeping bag for the pair of us. One is better than none, one each is at least feasible but adds to the cost and is very probably more than you need.
I've just been checking some kit lists from my own winter trips, and I reckon your last updated kit list pretty much has everything covered, assuming you don't need technical stuff for climbing or skiing, and you don't plan to travel in avalanche terrain (bit of a moot point there - avalanches do happen regularly enough in the Scottish hills, and the Lakes etc too, but apart from regular off-piste skiers I really can't see that most walkers are going to equip themselves with tranceivers and probes... shovels, at least as group items, are probably more realistic since they're relatively cheap and also more multi-use).
My main point would be don't underestimate the amount of warm clothing or other insulation you'd require to survive a prolonged period of enforced immobility. There's a difference between throwing on an extra layer for a quick lunch stop and sitting out hours in the worst weather, especially if there's limited natural shelter available. Pete's points about a mixture of blizzard bags, bivi bags and bothy shelters is a good one, as is sufficient stuff to press into service as ground insulation.
Something I'd emphasise to people - whatever flavour of hats, hood, balaclavas, buffs etc they have, together with their goggles they need to be able to completely cover their head, face and neck. Walking into a wind-driven blizzard, any exposed skin will feel like it's been sand-blasted and it can really hamper progress.
I'd put gaiters on the obligatory list if there's snow. Otherwise post-holing in deep snow is bound to see it getting inside your boots and melting. Wet socks in summer are an inconvenience, but in winter feet can get dangerously cold.
Finally, again particularly for snow, I'd say consider walking poles. Obviously you need to be aware when to put them away and get the axe out, but they can greatly assist progress and stability, and test out what's immediately ahead in a white-out. Baskets bigger than the little button ones that come on a lot of poles are handy too.
No real need to worry about cutting the blizzard bag as there is also a blanket version of the blizzard bag (weighs the same) http://www.blizzardsurvival.com/product.php/111/blizzard-survival-blanket-small
But I imagine that combined with a knife and some tape you would have more options. insulating poncho perhaps?
Don't neglect food, few places in the UK winter hills are more than a couple of hours from safety and its food you need to keep going. (Or for that matter dig a snow hole, survive a cold night, cope with injury). And when you do get back to the car at 3 in the morning you'll be grateful you took some extra scoff. And keep at least some of it on you, not in your pack.
My friends asked me for advice and rather than offering them a list, I thought I'd make a proposal, see what people thought and send them a link to the discussion. That way they get not my opinion but many different ones if not a consensus. I may still do that.
