Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture, industry, commerce, and social activities.
[1] In the United States, a cold spell is defined as the national average high temperature dropping below 20 °F (−7 °C).
Even some poorly protected indoor plumbing ruptures as water expands within them, causing much damage to property and costly insurance claims.
Recent research suggests a possible link between cold waves in North America and extratropical cyclogenesis over the East Atlantic.
[10] Examples include Rossby wave propagation from the North Pacific or an upper-level anticyclone west of Greenland.
[12] In some places, such as Siberia, extreme cold requires that fuel-powered machinery intended to be used occasionally must be run continually.
Energy conservation, difficult as it is in a cold wave, may require such measures as collecting people (especially the poor and elderly) in communal shelters.
[13] Hospitals can prepare for the admission of victims of frostbite and hypothermia; schools and other public buildings can be converted into shelters.
Vulnerable crops may be sprayed with water that will paradoxically protect the plants by freezing and absorbing the cold from surrounding air.
However, caution should be taken as the use of charcoal fires for cooking or heating within an enclosed dwelling is extremely dangerous due to carbon monoxide poisoning.