Actually, now that I look at the picture I realize that the culvert on the left must be already frozen solid, since on that side the ice is covered by a thin layer of snow. But on the right we see a fresh layer of ice, which must have formed there after the snow.

The thing is that as soon as the weather gets warmer, flowing water will start to carve a route in ice, naturally unblocking the culvert. But that only happens if there is enough space for the water to get through. So, at the moment it still looks like water can get through the other culvert, so there are chances that the situation will resolve itself as soon as we get Spring temperatures - unless the ice keeps accumulating and blocks the culvert before that. In which case hot water or steam is needed to open up a route.