In the last decades considerable efforts have been devoted to understanding single events related to friction, fracture and unjamming transition, commonly denominated avalanches. However, in many different natural scenarios-from subcritical fracture to earthquake dynamics-these events are of all scales; a situation that has often been interpreted within the formalism of critical phenomena, and having as a relevant consequence the inherently unpredictability of scale-invariant avalanches. A revision of this interpretation which departs from standard ideas is presented here, resulting in [1]:(i)critical systems are not necessarily unpredictable; (ii)slowly driven systems evolving through uncorrelated power-law distributed avalanches are not necessarily critical; and (iii) scale-invariant avalanches are not necessarily unpredictable. Simple simulations [2] and granular experiments [3] confirm the findings.

[1]O. Ramos, Scale invariant avalanches: a critical confusion; in B. Veress and J. Szigethy (eds.) Horizons in Earth Science Research. Vol. 3 (Nova Science Publishers) pp 157-188 (2011)arXiv:1104.4991v1.

[2]O. Ramos, Criticality in earthquakes. Good or bad for prediction? Tectonophysics, 485,321-326 (2010).

[3]O. Ramos, E. Altshuler, and K.J.Måløy, Avalanche prediction in a self-organized pile of beads, Phys. Rev. Lett. 102, 078701 (2009).