of course it is fake - simple chemistry would suggest that it is completely fake and that the resulting statements about foul smelling nucleation chemicals (stuff like silver iodide and sodium chloride used to form rain drops and snow flakes in high clouds) burning is false - neither of these chemicals give off an odour when burnt - sodium chloride is used in fire extinguishers for metal based fires and is used in small kitchen fires with spilled oil to retard flame generation - it does not burn off but does cause the formation of soot (see below) where carbon is present in the flame source
the lighters used are butane lighters as part of the combustion process with butane lighters, so that they burn a yellow - safety - flame, they also generate a lot of free carbon molecules that attach to the snow as soot.
the water in snow melt is initially reabsorbed by the compacted snow, giving rise to a slushier yet intact snow mass - the chances of sublimation occurring, i.e. ice to steam, are negligible
simple processes, easily understood, when clearly explained; unless you believe that most of what you saw in chemistry classes was magic