I was thinking about some suitable shelter that is compact and can be easily carried for emergencies, particularly in cold windy conditions. Mountain climbers regularly experience extreme conditions and their gear includes good lightweight clothing, tent, good sleeping bag and sometimes a candle.
Si think something similar, but smaller and lighter, can be achieved by an emergency shelter, inflating mattress/chair/pillow (floor insulation) and suitable clothing (what you wear in case of emergency). I guess it is not going to be a comfortable or long-term resting equipment, but good enough to survive. What do you think?

Then there is another extreme - heat. In this case, you need a sun protection (double layer of a sheet separated by air) installed on poles and hide under it. Maybe even excavate the ground to avoid ground heat. I guess it is already something relatively lightweight. Are there lighter alternatives?

Thanks