The North Warning System (NWS) is a series of radar stations across Arctic North America. It provides surveillance of airspace from potential incursions or attacks from across North America's polar region. The NWS consists of 13 long-range radars (11 in Canada of which 8 were DEW Line sites) and 39 short-range radars (26 in Canada). The state-of-the-art radar system forms a 4,800-kilometer-long and 320-kilometer-wide "tripwire" stretching from Alaska, via Canada, to Greenland.

NWS was established in 1985 when selected DEW Line stations were upgraded and merged with newly built stations into a more advanced early warning system. Automation was increased over the previous DEW Line system and a number of additional DEW Line stations were closed. In 1990, with the end of the Cold War and collapse of the Soviet Union, the U.S. Air Force withdrew remaining personnel from Canadian NWS stations and turned full operation over to the Canadian Armed Forces.

The system is controlled by the northern segment of NORAD from CFB North Bay.

See also:

• List of Canadian Forces bases

External links

• NORAD fact sheet (http://www.norad.mil/index.cfm?fuseaction=home.news_fact_nws) Public information.
• PAIL Corp. (http://www.pail.ca/nws.html) Public information from PAIL Corp.
• Technical Radar Information (http://www.fas.org/nuke/guide/usa/airdef/an-fps-124.htm) NWS Radar information from FAS.