If you want a more normal blocking you could try those:
Tree fell on the street
Car accident
If you are willing to do some more crayz stuff, you can try something like a plane crash, cliff or a radioactive waste disposal that kills everyone passing.
A few ideas are, a storm/sandstorm, mountains, quicksand, a creepy clown you can’t get near, and blurring the camera upon approach to the end of the map.