What caused the ice?

Glaze occurs when freezing rain passes. If warm air masses came to the cooled surface of the earth and brought rains. In winter after thaws with a sharp drop in temperature. In clear spring weather, during the day, the snow is actively melting, and at night, due to the absence of clouds, the earth is cooled, the melt water turns into ice. In any case, icing is a dangerous phenomenon. The weather forecast usually warns of its possible occurrence.