I'm thinking it would be kind of easier if it was the protagonist experiencing someone else in that situation. In that sense if they were in a situation (for example) where the protagonist was the best friend, of a girl who had just been dumped, not only would you have to describe her crying but the gestures she makes as well as the gestures the protagonist makes ( Oh, and metaphors help HEAPS .)
It was painful to see her like this. All I could do was embrace her and let the torrent of her tears to soak through my shirt. I could feel her clench her fists, not knowing whether to be mad or to give up hope all together. I could hear her silently screaming, suffocating with each breath she took holding onto her pride. I ran my fingers through her hair, time and time again, in an attempt to calm the silent war within her mind.
(That's not necessarily much good; I just wrote it in the spur of the moment.)
You need to take into consideration the type of character this person is. It sounds a little weird but everyone cries differently... like, they might be annoyed that they're crying, so they try to stop, but it makes it worse. Or in this case, they're angry, so their tears are described as a "torrent" because, well, a torrent or (if you want) an avalanche is destructive - a natural hazard which, if you get what I mean, seems "angry"... (I'm sorry if that doesn't make sense)
Also know that:
A person doesn't just "cry," so the way you describe how their tears fall needs to in some way reflect the situation they're in.
Someone may be crying out of happiness, crying out of anger, crying out of disappointment...
I'll give an example for each to make that easier to understand:
It was the best day of my life. My tears overflowed with joy and fell just like the bouquet that I had thrown.
Anger: (just like before)
She tried to hold back the seething torrent/avalanche of tears she to wash away her anger
Mot even the steady stream of liquid trickling down my face could cure my thirst for her. After all, she loved him, not me...
anyways yeah...I hoped that helped :)