Additional [c] info on November 20, 2018:
a. The watery storm lasts for somewhat between 40 to 65 minutes of screen time at least, is tremendous, and is going to demand a lot of effects time.
b. The previously stated non-outsourced world-space containing a huge object of astronomical proportion (as stated in the previous link below) is a larger comet, at least larger than what previously seen in season 1, may be much closer