could be it bigger drones are less affected but i think it is a mix of elements. it was pretty cold and really humid as it was a thick fog. So after a while the whole propeller was covered with ice, so there was no angle for it to generate lift.
the same also happened few years ago, but i didn't see the ice and thought it was just a weird malfunction. and i was pretty stressed out seeing it hitting the ground and bouncing. now i was more or less ok with what ever would happen, as it already survived more than i thought it will :)
At least it landed on a ground, my favorite spot is a lake surrounded with forest. A lot of birds there plus view is fantastic, but I don't think I would be able to retrieve a drone and a heavy moisture and fog are default settings up there.
For the better lift the only thing that crosses my mind is stronger engine, a bit difference in weight is neglectable as an engine carries itself.
As for sensors, I think there should be different types. Once we traveled by a car thought the zero visibility fog, we couldn't move and I mounted my phone on a dashboard to see through that, it worked. So there must be a drone that has something similar.
For the one that you have, maybe you could install stronger or brighter lights, if you have an option for that. All police drones are equipped with various tech, but different piercing types or lights are pretty much on all that I saw so far.
Mine doesn't have any of that, so thank you for the information, it came in right time.
i generally don't like to fly in fog (at least not far so i don't know where the drone is :) ).
This one survived 30 days on a tree, so i wrote it off then :D all of this is just a bonus in his drone life :D
never thought of trying to use a phone to see better in for, but maybe it makes sense. interesting.