Purchase sidewalk salt also called calcium chloride from your local hardware or big box store.
Snow melt patterns on roof.
Besides wasted heat melting snow on roofs can mean ice dams where snow melts in a warmer spot on the roof and then freezes when it hits the cold eaves.
If your attic has little or no insulation the snow will disappear quickly.
The differences from house to house new or old can be very impressive.
Place this vertically on your roof near the edge so it will melt a section of snow and ice creating an area where the water can leak off.
The patterns relate to attic insulation.
As you look at the patterns the mosaic of patterns will show which homes are more air tight and well insulated than others.
If your attic insulation needs a fix the pattern will be patchy.
When snow begins to gradually melt off a roof vehicle or other outside structure you might occasionally see some odd patterns develop.
On frosty and snowy mornings melt patterns will become readily visible.
Because the snow is melting from a heat loss on your roof and not because of warming temperatures the melted snow can refreeze once it travels from your roof creating ice dams that appear as icicles on the eaves and gutters.