John Wheeler: Melting snow can be just as slippery as ice
Ice is slippery because the pressure of weight causes a thin layer of the ice to melt.
FARGO — Occasional mild days and the higher sun angle this time of year can be good for melting snow. However, driving through partially melted snow and ice can still be tricky. Slush is a mixture of ice and water, and it can make a surface very slippery, particularly when the ground temperature is below freezing. In fact, ice is slippery because the pressure of weight causes a thin layer of the ice to melt. When you slip on ice, you are actually slipping on this layer of water.
Ice skates glide so well on the ice because they concentrate the pressure of the skater’s weight into the very narrow space under the blade, where the ice melts. When a vehicle moving down a road encounters slush, this water and ice combination can make it hard to stop. Steering may also be affected if a wall of slush forms alongside the tires, which may cause the driver to lose control of the vehicle.