Have you heard the recent weather addressed as “a deep freeze”? You may be familiar with a deep freezer or a refrigerator in which food can be quickly frozen and kept for long periods at a very low temperature. The Urban dictionary has a meteorological definition of a deep freeze as “Extreme cold temps due to the rapid movement of Arctic air. Associated with the polar vortex weather system.” The International Institute of Refrigeration recommends a minimum 0 °F, or -18 °C for maintaining frozen foods – the best compromise between food preservation and energy savings. Our recent air temperatures in the subzero range definitely qualify as being in the “Deep Freeze”.
Mary Knapp, Weather Data Library