There are a few things that can cause a slash in a tire, the most common being debris on the road. This could be anything from a piece of metal or glass to a nail or even just a sharp rock. If you hit something like this while driving, it can cause a slash in your tire. Another thing that can cause a slash in your tire is if you drive over something sharp, like barbed wire or construction debris. This can also happen if you park your car on an uneven surface and one of the tires gets caught on something sharp.
If you do end up with a slash in your tire, it's important to get it fixed as soon as possible. If you don't, the tire could lose air and eventually go flat. This could leave you stranded on the side of the road or even cause an accident if you're driving at high speeds when it happens. To avoid this, make sure to check your tires regularly for any signs of damage and have them repaired or replaced as necessary.