M5 + snow + winter tires

[Z4MCSL]

I have an f10 m5 which I love but is hard to use the power in anything other than bone dry conditions

I've read a lot about it being fine on winter tires in the snow and driving to the alps should be no issue (which is my plan)

However I parked on grass the other day

It was slightly damp when leaving the field up a slope and the car just couldn't do it going forwards - I ended up reversing and it was just about fine.

I know how amazing winter tires are having driven a rental Ford s max on winter tires through a blizzard that 4x4s without winter tires were getting stuck in.... but still feeling hesitant to commit to a journey on winter tires if at the end the parking situation involves a fair amount of ice and snow

Thanks in advance