In discharges on the Joint European Torus (JET) with safety factor q(0) < 1 and high power Ion Cyclotron Resonance Heating (ICRH), monster sawtooth crashes are preceded by sweeping frequency 'tornado modes' in the TAE frequency range. A suite of equilibrium and spectral MHD codes is used for explaining the observed evolution of the tornado mode frequency and for identifying temporal evolution of the safety factor inside the q = 1 radius just before sawtooth crashes. In some cases, the tornado modes are observed simultaneously with both positive and negative toroidal mode numbers. Hence, a free energy source other than the radial gradient of the energetic ion pressure exciting these modes is sought. The distribution function of the ICRH-accelerated ions is assessed with the SELFO code and energetic particle drive due to the velocity space anisotropy of ICRH-accelerated ions is considered analytically as the possible source for excitation of bi-directional tornado modes.