We have discovered that there are a number of plants that can survive our cold temperatures, but cannot tolerate winter moisture. A good example are many of the barrel type cacti which are naturally found in very cold mountainous regions, but regions that receive no winter rainfall. The opposite effect is equally dramatic. Gardeners whose gardens are covered in snow most of the winter are often able to grow plants, especially perennials, nearly two zones outside their normal range, due to the insulating effect of the snow. On woody plants, a snow layer will often protect the roots and lower branches of a plant, while the top growth is killed back to the snow line.
Ice is an entirely different matter.
Ice doesn't have the insulating effect as snow since there are no buffering air spaces. As the water freezes, it releases heat. As soon as the water application ceases, the protection disappears also. There are a few factors, that we as gardeners can control. Some plants tend to continue growing, despite cold temperatures and reduced day length.