  We demonstrate a simple cascade mechanism that drives the formation and
emergence of rogue waves in the generalized non-linear Schr\"{o}dinger equation
with third-order dispersion. This conceptually novel generation mechanism is
based on inelastic collisions of quasi-solitons and is well described by a
resonant-like scattering behaviour for the energy transfer in pair-wise
quasi-soliton collisions. Our results demonstrate a threshold for rogue wave
emergence and the existence of a period of reduced amplitudes - a "calm before
the storm" - preceding the arrival of a rogue wave event. Comparing with
ultra-long time window simulations of $3.865\times 10^{6}$ps we observe the
statistics of rogue waves in optical fibres with an unprecedented level of
detail and accuracy, unambiguously establishing the long-ranged character of
the rogue wave power-distribution function over seven orders of magnitude.
