北海道の海岸に向かう途中で、川に入ってしまったのかもしれません。
They might have ended up entering the river en route to the Hokkaido coast.
What is の (in bold) doing in this sentence? It was my understanding that かもしれない came straight after the predicate.
My guess is that this is the so-called 'explanatory の' rather than a nominaliser. Please can you confirm or correct my thoughts?