What is one of Poseidon's many powers?

The Call to Adventure
The hero begins in a situation of normality from which some information is received that acts as a call to head off into the unknown. According to Campbell, this region is represented by

a distant land, a forest, a kingdom underground, beneath the waves, or above the sky, a secret island, lofty mountaintop, or profound dream state; but it is always a place of strangely fluid and polymorphous beings, unimaginable torments, superhuman deeds, and impossible delight. The hero can go forth of their own volition to accomplish the adventure, as did Theseus when he arrived in his father's city, Athens, and heard the horrible history of the Minotaur; or they may be carried or sent abroad by some benign or malignant agent as was Odysseus, driven about the Mediterranean by the winds of the angered god, Poseidon. The adventure may begin as a mere blunder... or still, again, one may be only casually strolling when some passing phenomenon catches the wandering eye and lures one away from the frequented paths of man. Examples might be multiplied, ad infinitum, from every corner of the world.[18]

Poseidon has power to control the winds that guide ships on the seas of the Mediterranean.