Mazu is able to see in her minds eye her brothers struggling to survive at sea during the typhoon. She is able to guide them to the largest pieces of wood so they can stay afloat. Why does mazu most likely have these powers

Mazu had these powers because she had been touched by the gods.

Explanation:

Mazu was not an ordinary person anymore she wasn't just Mazu any longer after she fell into a trance. This was because the gods had touched her. They touched her out of admiration. They felt she was courageous and had no need to show off. They considered this the rarest form of courage. It was through the trance that she was able to guide her brothers to the largest pieces of wood so they could remain afloat on water.

Therefore the reason she had these powers was because the gods had touched her and she was no longer an ordinary person.