Tatami Mat on the Flood: Fantasy

She woke when the tatami mat beneath her became damp with silt water from the rice fields. She had had a dream that the moon goddess was reaching down to shake her by the shoulder, crying sad tears that washed over her face and dampened her hair. When her eyes opened, at first she thought that the tears were still falling--then she tasted the silt in her mouth and sat bolt upright. She was going to cry out that the paddies were flooding and they should bring all their goods to the rooftop, but her mouth froze, open. She was floating on a wide sea--she sat on her tatami mat as it spun through--

Inspiration: "1982--Floods in Japan kill 200"
Story Potential: High.
Notes: Practical explanation or magic tatami mat?