M O O N that spells Moon!
:D
The Stand is probably my favorite of King's stories.
Big moons make for huge tides. Probably why most of Winterhold got washed away.

Big moons and/or close moons.
Interestingly, tidal forces don't just effect oceans, but also the atmosphere itself rises and falls with the tide, and to a smaller extent even the planet's crust can be shifted thanks to those gravitational tugs. This would then not only result in the oceans rising very high, but the atmosphere thinning as it is pulled dozens of miles higher as well as seismic turmoil like more and larger earthquakes and volcanic eruptions. Further, I might even be concerned that the planet and moon would end up tidally locked, kind of like the Kuiper belt object Pluto and its companion Charon. I suppose Earth didn't get tidally locked with the moon (although the moon is locked such that the same hemisphere permanently faces Earth) might be due to the fact that the Earth was rotating so much faster in its early life, having been gradually slowed by the moon's pull tot he speed we rotate at now.