It was not because of ice / sea level or geographically position.
The reason why because the city are flooded by the sea was because of the moon.
In the galaxy far far away, there are lot of black holes. This black holes move all over the galaxy, sucking everything along their path, sucking rocks and drop it somewhere, sometime it drop on planet earth, hence they called it asteriod.
Our moon, according to NASA, is further and further away from our Earth, because of black holes. One day, maybe 500 years later, maybe 1000, maybe 2000. The moon will disappear.
You might asked "the moon gone so wat does it got to do with storm??".
Well, our earth rotatation depands on the moon, if the moon is gone, the earth rotation will change. just like a cup of water, you rotate it the other way the water will flow out.