A tsunami that hits at night leaves even more fluid than normal. It's dark at night, so the sun isn't there to help evaporate all that tsunami liquid.
This fluid stays in the 駅 (えき) longer than anywhere else. All of those tsunami liquids pour deep inside the 駅 late at night and the sun still can't reach them to help evaporate them during the day. It's a real *night*mare.
Currently there are no similar looking kanji which exist in the WaniKani learning system