No one thinks they’re going to be trapped by whiteout conditions or separated from their group as night falls but it happens with alarming regularity. Don’t make things worse by being unprepared. These advanced Mylar emergency blankets cost less than 4 bucks each and weigh virtually nothing and yet can and do save lives. They’re waterproof, tear-resistant survival gear that comes in a pack of 5. As such there’s no excuse for not having them tucked away in your backpack or daypack when you set out. The very definition of essential survival gear for outdoorsmen of all stripes.
For global catastrophic risks the costs of food storage become impractical for most of the population  and for some such catastrophes conventional agriculture would not function due to the loss of a large fraction of sunlight (e.g. during nuclear winter or a supervolcano). In such situations, alternative food is necessary, which is converting natural gas and wood fiber to human edible food.
Say you're at work and a terrorist attack occurs. Roads are closed to any and all traffic but you only want to get home - even if that means walking. You may not want to grab your full on family pack in the car or you may not even be able to get to it. But you just want a light kit to get you through. How far is it to get home from wherever you may be? This get home kit should provide for 1-3 nights of traveling on foot till you make it home.