u/AdPractical8107

Saw a post about water in the basement and some good ideas, I've already started fixing the grade around the house but I fear this might be something more. Water started to pool on the corner of the first picture and when I came home from work the basement had completely flooded. Any ideas? On what could cause the basement to flood this badly? The walls did not feel wet to the touch, however the corner of the bench on the first picture was damp.

EDIT: 2nd picture is supposed to be a video, here's the link https://streamable.com/a3zfh8