Overlay of the WKB predictions for the divergence of the diffusion flux N div(ℱ_tot) on top of the contours of the DF in action-space measured in the S12 simulation. The black background contours are the levels contours of the DF at time t_S12 = 1400 (see the lower panel of Fig. 7 of S12). These contours are spaced linearly between 95% and 5% of the DF maximum and exhibit clearly the appearance of a resonant ridge. The coloured transparent contours correspond to the predicted values of N div(ℱ_tot) using the same conventions as in Fig. 9. We note that the developed late time ridge is consistent with the predicted depletion (red) and enrichment (blue) of orbits.