Learn English – What single word can replace ‘nearly never’ in ‘It nearly never occurs’

I am talking about an event that is nearly never observed, but I don't want to say "it does not happen" but this would not be correct. Is it possible to write

It nearly never occurs.

with a single word for "nearly never".

I've found "almost never" could be a good choice, but I would like a single word if this exists.

context : Fires "nearly never" occur more than once in the same year.

EDIT :

I consider that fires are already a "rare event". A second fire in a place that has already burnt (therefore with usually no more inflammable substances) should therefore not occur. However, it does sometime occur (with a very small probability) when the first fire did not burn everything and there is a new start of fire and the external conditions are favourable to fire etc. Hence my quest for a "nearly never" word, which I didn't like.

I had several answer and I thank all who answered. However, most answers provide more than one solution so I cannot make the difference between good "answers" and good "solutions" based on the vote. I personnally see three options :

option 1 : forget about using a single word and use "almost never"

option 2 : use "rarely" (voted up in the comment, voted down in one answer (or maybe the answer was voted down because it was too short) because almost never is too strong. But as I said I am looking for something strong, maybe something between "almost never" which seems to be used for probability of "0" and rarely (probability of 0.0001). In my case it is like a probability of 0.000000001.

option 3 : use scarcely, which is the closest match to "almost never". @helix mentioned it and the definition seemed appropriate in my case.