system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does snow leave my car so dirty?

You'd of thought that it would clean it if anything?
gpt
Are you talking about driving around in a place like New England during the winter? If so it's not the snow that makes your car dirty - its mostly the salt they lay down and some crud on the road. The road is wet and very briney during/after a snow storm in an area that salts because the salt melts the snow, so as you and other cars drive around the tires throw it into the air and it sticks to your car.

So while salt is the most of it there is also dirt and stuff being flung up too.  There are people who keep their cars highly detailed that won't drive when it rains for this reason, even in summer.