Subject: heat of fusion and the water cycle... how do they fit together?

Dear Sir/Madam,

I am 14 and taking Physical Science. We are learning about the hydrologic 
cycle, and recently were assigned a project ( drawing/labeling the cycle)
where "Heat of Fusion" was given as something to label on our diagram. The 
project is due tomorrow and I absolutely do not expect to have this answered 
by then, just to have my curiousity quenched. Although my teacher could answer 
my question, I would prefer it was done so by a professional. My question is: 

How/Where does the Heat of Fusion fit into the water cycle?

Thank you profoundly for your time/ effort!

Sincerely,
Jennifer

Re: heat of fusion and the water cycle... how do they fit together?