Frost happens when the temperature of the plant is below freezing; this is why we have frost delays when the air temperature is 38 degrees. Essentially, frost is frozen dew. Ice crystals form on both the outside and inside of the plant. When there is traffic, grass plants that have frost the plant tissues actually ruptures. The damage won’t be seen right away, but the next day the cart tracks or the footprints will appear black. This is because that plant is dead and won’t be able to repair itself.  For some perspective, just one foursome can leave up to a hundred footprints on one green that would be a lot of dead plants.  There are certain situations where we can water off the frost, which will essentially melt the ice that is creating the frost delay.