Structural Crack in Concrete Stairs
This is from a weak point in the concrete. The size and length of the crack tells me that there could be a soil problem with my guess being a water drainage issue. The erosion from the sprinklers or poor site drainage has undermined the stairs causing it to put pressure on the weakest point of the concrete stairs causing them to crack. This is a noticeable crack , you could start moving some dirt around the stairs to help with soil erosion.