Output data averaging
After source research in the source, it appears that most of the fluxes are accumulated over the ts_write time before output, i.e. in the example the MS_EVAP is kn kg/m^2/3h. It would be easier to write everithing in SI units, to avoid this kind of questions. In addition, it is not really cleat from the code to see where the accumulation append (surfacefluxes.mass is updated by addition at any new time step, and in main a reset is called after the TS are written. In my opinion, it would be easier the snowpack data are only on a per time step basis (i.e. no accumulation in SN inner data), and if needed some accumulation variable are defined in the main. This would be clear and far less prone to error. Indeed, if in the current version someone use surfacefluxes.mass, he will actually use the accumulated value since the last writing of the TS, which would be completely wrong. This is why I propose to have accumulation handled in the main.cc only, and keep snowpack variable only in snowpack timestep basis. Then the main can do the proper averaging and accumulation before writing the data.