Leaves with snow/frost on them.

Cold Wave

A Cold Wave is a rapid fall in temperature within 24 hours and extreme low temperatures for an extended period. The temperatures classified as a cold wave are dependent on the location and defined by the local National Weather Service (NWS) weather forecast office.

In the National Risk Index, a Cold Wave Risk Index score and rating represent a community's relative risk for Cold Waves when compared to the rest of the United States. A Cold Wave Expected Annual Loss score and rating represent a community's relative level of expected building, population, and agriculture loss each year due to Cold Waves when compared to the rest of the United States.

A map of the United States colored by Cold Wave Risk Index ratings. Cold Wave risk is prevalent in most of the northern half of the United States, and is most likely in the northern Midwest, northwest Maine, northern New Hampshire, northern Vermont, northwestern New York, northern Alaska, southeast Idaho, north central and eastern Montana, eastern Wyoming, eastern Washington, and eastern Oregon. For full results, see the National Risk Index Map webpage.

Cold Wave Exposure

A Cold Wave exposure value represents a community's building value (in dollars), population (in both people and population equivalence), and agriculture value (in dollars) exposed to Cold Waves.

Cold Wave Annualized Frequency

A Cold Wave annualized frequency value represents the average number of recorded Cold Wave hazard occurrences (event-days) per year over the period of record (12.14 years).

Cold Wave Historic Loss Ratio

A Cold Wave historic loss ratio is the representative percentage of the exposed consequence type value (building, population, or agriculture) expected to be lost due to a Cold Wave hazard occurrence.

Cold Wave Processing Methodology

For comprehensive details about the Cold Wave processing methodology, see the National Risk Index Technical Documentation.