I think what you describe is the classic dilemma for anyone who goes into the mountains for a ‘day trip’ - be they alpinists, skiers or crystal hunters - the mountains being a place that can easily confound your plans!
As with alpinism, you’re making a judgement based on experience (if you have neither then employ a guide or take up Alpine knitting), on much insurance do I need to take out? If you take up too much and it ends up creating the event (being so slow you get benighted) you’ll curse yourself, but if you take too little, and get benighted due to a lost ski, a twisted ankle or simply being too ambitious, you’ll curse yourself… if you make it through the night.
I write quite a bit about survivability, and this comes in to play here, being balanced against the type of situation you’ll be needing to survive. You will not be trapped on the summit of a winter peak at minus twenty, nor forced to climb for days and days to get out of a sticky situation. What you’ll need to survive is one enforced night out in the wilds, wilds that actually offer a lot of tools to aid in that survival.
But first off try and run some scenarios in your head. Think back to some near benightments and ask yourself what if you’d not made it back, what would you have done? Try and think what you could have improvised from the kit you had to make it through the night?
Now what you may imagine would be adequate while sat at an office desk in a nice warm office, hydrated, rested, and with a sandwich in your belly is very different to that twilight hour, damp, cold, lost, hungry and so tired you can’t push on. If you were to really consider this situation then you should ideally do it next time you feel like that. Stop with your partner(s) just before the end of the day and say “Ok - what if we had to bivy now, how would we do it? What do we have and would we survive?). Better still why not see how you feel playing the scenario out, getting set up to bivy, but knowing once you get cold you can nip back home.
I wrote many thousands of words about being benighted without any kit, but when it did happen (it’s happened a few times), I had the bare essentials to make it liveable, but what I underestimated was the way exhaustion kind of levelled everything out. When you’re that tired you can put up with a great deal of discomfort simply because you’re asleep.
For me, setting out on the types of trips you describe, I’d be doing the old Alpinists juggle of weight and function and survivability, playing around with skills, toughness, technique and the quality/design of my gear.
Here would be the gear I would choose and why:
- Static clothing layer: This would be a heavy-duty warm ‘belay style jacket’ made from down or synthetic fill (not the lightweight jackets, but mid to heavy). This jacket can be worn for an enforced bivy, worn at stops in the day (dress to move, throw on a layer when you stop), but also thrown on when you need a castle to hide in when moving in bad weather or when you get wet and cold. It can also be used with other peoples jackets to keep a casualty warm. If you wanted you could add a pair of superlight insulated ‘puff’ style pants, which again can be worn when static or when active, and take up very little space.
- Shovel: This is your most important piece of survival kit after your clothes as with it you can dig a snow hole or snow pit, or build a wall to hide behind. Get a metal shovel (BD for example) and avoid plastic.
- Snow Saw: Having a lightweight snow saw is handy when it comes to building snow walls (which can be very effective if used with a bothy bag and under insulation). They can also be used to make an igloo (or a lesser version) the condo of all snow bivys. Practice digging survival trenches, using the saw to cut and shape the roof (use your avalanche probe to check for depth before you start).
- Foam Matt: This would be a full weight thickness mat cut down to fit in your pack, not the usual skinny mat included (only good for warm weather bivys). You can add a layer of foam in the back, and the front of the pack, as this increases your available insulation, but also helps to protect the contents when falling. It’s vital to stay off the snow in a bivy so make sure you employ your skis, packs, skins, rope, harness and everything else you have to block you from its contact.
- Bivy Bag: The Blizzard bag is a great alternative to a breathable or tin foil bivy bag, as it provides a huge increase in protection and warmth, and is probably the minimum you’d want for winter bivys.
- Bothy Bag: This is a must item and you need to have one big enough for the whole team (2 or 4 person). This will really save your ice in a dicey situation and extends your survivability, as well as morale, dramatically. It’s also great for stops (fixing a ski or someone’s feet) or at lunch breaks. You can use your ski poles to help keep the bag off you if you bivy, plus a bright colour makes an idea rescue marker.
- Stove: You should never go into the hills without some way of both melting snow and making water. Having a tiny pocket rocket style burner, large titanium mug, flint and steel (will not get wet), matches,100ml gas canister, lighter, foil windshield, and some basic food that can be heated (soup, noodles) can make make a big dent in your suffering. With this, you can also meltwater, or heat water to pure into a Nalgene bottle to warm up a casualty (also a good idea for enforced bivys). This stove will also heat up a bothy bag for the few minutes you run it, warming you up in the process and taking the edge of things. The weight of this stove between two or more people is minimal.
- Survival Candle: A strange thing to carry you may think, but inside a bothy bag one of these will provide both heat and light and help you make it through the night.
- Heat pads: Carry a few of these in your emergency kit, as they can be used by people who are suffering, stuffed in boots, held in cold hands etc. Replace regularly as they go off.
- Light: Always make sure you have enough batteries to see you through a full night, and consider at least one spare headtorch per team.
- Food: Always carry a small emergency supply of hill food that will remain always in your pack, such as one or two energy bars wrapped in duct tape.
- Matches and a knife: If you end up in a forested area you may be able to make a fire, but you’ll need matches and a knife to get all Bear Grylls on its ass!
- Bits: Make sure you have stuff like a whistle (daft item until you realise how good it is!), a cheap mobile phone (holds its charge better than a fancy new one, meaning you tell someone you’re benighted and will be down tomorrow), and an adequate repair/first aid kit, so you can avoid getting benighted in the first place!