If I understood your question correctly here is my solution:

Q(x,y,t)*A(x,y,t)*dt=SWE.

where Q is your snow melt flux (kg/(m2 sec)), A is area this flux is valid for (m2) and dt is timestep in sec.  If your flux is actually energy flux from an area, than you can assume that the snowpack is isothermal and just divide this flux by specific heat of fusion. If you have further questions, please contact me. Your initial question kind of lacks details, so it is hard to answer.

thanks buddy for your kind reply

@ Matvey Debolskiy

Can you please provide me the reference of this particular equation !

Aniket Gupta you don't need a reference for that.

It's just the flux definition.

dQ/dx/dy=dSWE/dt

then you can integrate it over the area. (And assume Q and SWE uniform, not dependant on x and y). After that, you integrate over time:

inegral(Q)dt=SWE that will give you specific SWE,

if you do want total volume:

integral(Q*A)dt=SWE(volume);