The freezing problem of mineral water

There is supercooling under natural conditions, that is, water will not freeze immediately below zero. When its stable state is destroyed, such as shock, adding crystal particles, etc. , soon frozen. This situation is often due to the high purity of water, for example, the water in the refrigerator is condensed by steam, and the purity is very high. Snow, drift, hail, etc. This happens to all those generated in high altitude, but they may have melted after being generated, or the temperature may drop at different rates.