Carabiners are rated to 4000kgs if I remember correctly.
As the winter temps. are routinely -20c or below, I don’t keep water in the car as it just freezes. I mentioned I have a bunch of other stuff in the car, one of which is a spirit stove with fuel, so if I need water I would melt the ice/snow.
Yes, it is essential you check your winter gear to make sure it’s up to the task!
Thanks for the comments so far