Multiple Harrowings in 1 year, why haven't folk there left already

If the Harrowing was something that happened once every so years I see how people could fight it or try their luck through the darkness... (I know now that is rather inconsistent, but my point remains :3)

Happening once, or even multiple times a year, makes no sense for common folk to hold their ground (even more because it's not actual people they're fighting, but dead things, who can't be defeated)

And from what we read from the Shadow and Fortune event - where the dead took whole ships, the ghost Kraken destroyed a whole neighborhood - My question is, how is Bilgewater still up and running? In just one go Bilgewater got completely wrecked. Lots of people have died, the story having turned out to be grim as it is, and if it happens 2+ times in the same year? People would be migrating (even if illegaly) somewhere else for sure.

I love reading it and it's exciting, but I don't see how people actually stay in Bilgewater, knowing what hunts it very so often... I'm saying here that with these events it should've been explored by the writters clear and definite ways the people there fight off the dead, or keep them away. I'm talking about candles and lamb sacrifices, chalk drewn pentagrams and that sort of things.

Happens once, "what was that?", happens twice "we should get the f outta here"

These events opened up the world a bit but I hope for future Harrowings of this scope we get more information on what can trigger it (the dead simply decide to go for it? too much sin accumulated?), and what people over the decades started doing to help themselves and if the dead have an agenda of their own.

I think it would've been logical for Bilgewater to be better equipped against Harrowings though, like iron walls that would slide through a whole building façade shutting it close completely.

And what about the tunnels beneath the city?

The walls of the cave were pale limestone, gouged from the cliffs upon which Bilgewater was built. The motion of water and the stone picks of the natives had crafted a labyrinth beneath the city few knew of or even suspected existed. The pale rock walls were etched with looping spirals, rippling waves and things that might have been unblinking eyes.

That's what I'm talking about, just not many BW inhabitants know about it...