Salt never loses its capability to melt snow and ice no matter how long it is stored. Rock salt is already between 210 and 320 million years old when it is mined. Carrying over salt on storage piles to the next year or even longer does not diminish the salt’s melting power. There is no loss to moisture from the air if salt is stored properly. Salt does not absorb moisture until the humidity reaches 75 percent. Any absorbed moisture will evaporate when the humidity falls below 75 percent. Any resulting thin crust on the surface of the salt is easily broken up.
Salt, however, can be lost to precipitation. Storage piles, whether large or small, should never be left exposed to rain or snow. A permanent under-roof storage facility is best for protecting salt. If this is not possible, then outside piles should be built on impermeable bituminous pads and covered with one of the many types of temporary waterproof materials, such as tarpaulins and polyethylene. These two rules – under cover and on a pad – will also prevent environmental problems from salt-laden runoff.
Storage in a roofed enclosure will:
- Prevent formation of lumpy salt that is difficult to handle with loaders and to move through spreaders
- Eliminate the possibility of contaminating streams and wells with salt runoff
- Eliminate salt loss through dissolving and runoff
Salt storage also an “insurance policy” that enables an agency to take delivery of its salt requirements so that when storms hit and everyone is scrambling, your community will know its crews have what they need to keep the roads safe and accessible. A good guideline for salt storage capacity is to have, under roof, enough salt for a full, average winter.