Merlin conjures a cyclone of wind.
Whirlwind Spell is a powerful incantation that conjures a contained cyclone of wind. This is a form of elemental magic that controls Air and Wind.
Merlin used such a spell – with the incantation "Cume þoden" ("I summon the wind") – to drive off Kanen's force of brigands during the Battle of Ealdor (The Moment of Truth).
Emrys attacks Morgana.
Merlin, disguised, with the help of an ageing spell, as "Dragoon the Great", went to Morgana's hovel to kill the Fomorroh that was controlling his mind. The warlock and the witch engaged in a magical battle in which they both used stunning spells to knock each other out. Morgana seemed to emerge victorious but Merlin gathered his magical strength and summoned a terrible whirlwind, against which Morgana was defenseless. The incantation Emrys used was: "Ic her aciege ænne windræs! Færblæd wawe! Windræs ungetermed: gehiere! Ic ðe bebiede mid ealle strangnesse ðæt ðu geblæwest ond sierest strange! Ge spurne þeos hægtesse!" Morgana was sent flying away and knocked unconscious, badly wounded (A Servant of Two Masters).
It was actually revealed, in the audio commentary of Ep.7, that Morgana was on the verge of dying from this spell and about to enter the Spirit world, but Morgause saved her by giving her a coin that would bring her back to the world of the living.