Extinction level event? Not quite, but it certainly is for the Goblin Empire.
The aftermath is written clearly on the faces of the party, who cannot quite believe what their unusual travel companion has just done. Possibly because it is impossible, and partially because this... was unexpected. Until now Kane the Uncouth has merely reacted, not taking matters in her own hands save at the Hillbilly giant fort, where she discarded Britomart's logical and cautious plan, to instead simply overwhelm the giants.
Here, she is still hurt and angry over Leonitas' death, and everything on this quest has been leading to this for her- taking an active stand and using her powers to do something no one else could do- stop the rampaging horde of the Goblin army that threatens to overwhelm the other humanoids of Urth.
For the first time in a long time, Veronica Kane is making a stand.
Props to Walt Simonson for Ronni's trademark 'THOOM', and to Howard Chaykin for teaching me to make the sound effect part of the panel.
While physics might have been tossed out the window for most of this sequence, justified with comic book "super powers" logic, as an artist I always try and maintain enough verisimilitude to maintain just ENOUGH physics. It helps with the suspension of disbelief inherent in the premise of enough background physics remain intact.
Hence the attention paid to the effects of Ronni's actions. Elements like the visible shockwaves, the bulging UP of the underside of the mountaintop in its center as she slams it down, the shockwave blowing up the cannons on the hillside NEXT to Igglehoop, the clouds overhead spreading from the shockwave, and the effect of the team being launched back by the force of impact, all hopefully help to sell the power of the event.