Is "fire" an uncountable noun? There are times when you can say "fires" too, right?
It can be either countable or uncountable depending on the meaning.
Word "fire" can be used in different meanings. If you use this word as the name of the element (like water or air), then it is uncountable.
Fire spreaded quickly because of strong wind.
Sometimes it can be used in the meaning of 'camp fire', then it is a countable noun.
Around the camp soldiers were sitting by fires.