That isn't always feasible: sometimes lumps, such as large investment projects or certain wage deals, are not public information, or at least not until after they've happened. By contrast, natural disasters are the canonical example of bumps that you can't fully predict, but you can anticipate as a possibility. And it's obvious when they've happened.
The effect of the drought on rural production and food prices is a good example of this. So were the two recent disasters affecting the iron ore market. The early months of the year are cyclone season in the Pilbara, so some disruptions to production can be reasonably anticipated, but Cyclone Veronica was far more disruptive than most.