Measurements of snow metamorphism and superimposed ice formation and the associatedmeteorological boundary conditions are presented. The observations were performed duringmelt onset, between May 20 and June 03, 2002, on first-year fast ice in Kongsfjorden,Svalbard. During the observation period, meteorological conditions changed from typical late-winterto summer conditions. This transition was characterized by a major change in the long-waveradiation fluxes, and associated air and snow temperature increases. Consequently,extensive snow melt was observed and the transformation of snow into superimposed ice. The0.23 m thick snow cover completely disappeared within 5 days, and was transformed into 5 to6 cm of superimposed ice, covered by a thin layer of deteriorated ice.