What are the Chances of this nuclear war not happing?
None N Korea is going to Nuke the ocean not too far from Hawaii and it's going to cause a tsunami wave that is goin to wash the west coast off the map.
Kim Jung thinks he can do more damage this way and his missiles can't reach into the Continental US yet so he is going to do it this way.
Underwater nuclear tests have been taking place since the 1950s and no tsunami has resulted in any of those. You would need a nuclear bomb at least hundreds times more powerful than the Tsar bomb to pull off a tsunami. There are YouTube videos of underwater and overwater nuclear tests taking place, and they clearly show no tsunami as a result.
Now if someone were to place a nuclear bomb under the seabed near a fault line on the other hand... its a possibility, but most fault lines are at depths in the ocean where the pressure is so great, it would crush the bomb before it even made it to the bottom.
Tsunami bomb - Wikipedia
You would need A LOT of explosives to create a tsunami. And also a lot more to create a tsunami capable of reaching the western coast of the United States.
We're talking about gigantic volumes of water here, its the ocean. You need a very big explosion to pull that off. North Korea doesn't have that capability. Russia does, perhaps. China perhaps. United States perhaps. North Korea? No.