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The Distant Early Warning Line, also known as the DEW Line or Early Warning Line, was a system of
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
stations in the northern
Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
region of Canada, with additional stations along the north coast and
Aleutian Islands The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...
of
Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
(see Project Stretchout and Project Bluegrass), in addition to the
Faroe Islands The Faroe Islands ( ) (alt. the Faroes) are an archipelago in the North Atlantic Ocean and an autonomous territory of the Danish Realm, Kingdom of Denmark. Located between Iceland, Norway, and the United Kingdom, the islands have a populat ...
,
Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...
, and
Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...
. It was set up to detect incoming
bomber A bomber is a military combat aircraft that utilizes air-to-ground weaponry to drop bombs, launch aerial torpedo, torpedoes, or deploy air-launched cruise missiles. There are two major classifications of bomber: strategic and tactical. Strateg ...
s of the
Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
during the
Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
, and provide early warning of any sea-and-land invasion. The DEW Line was the northernmost and most capable of three radar lines in Canada and Alaska. The first of these was the joint Canadian-United States Pinetree Line, which ran from
Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...
to
Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...
just north of the
Canada–United States border The international border between Canada and the United States is the longest in the world by total length. The boundary (including boundaries in the Great Lakes, Atlantic, and Pacific coasts) is long. The land border has two sections: Canada' ...
, but even while it was being built there were concerns that it would not provide enough warning time to launch an effective counterattack. The Mid-Canada Line (MCL) was proposed as an inexpensive solution using bistatic radar. This provided a "trip wire" warning located roughly at the 55th parallel, giving commanders ample warning time, but little information on the targets or their exact location. The MCL proved largely useless in practice, as the radar return of flocks of birds overwhelmed signals from aircraft. The DEW Line was proposed as a solution to both of these problems, using conventional radar systems that could both detect and characterise an attack, while being located far to the north where they would offer hours of advance warning. This would not only provide ample time for the defences to prepare, but also allow the
Strategic Air Command Strategic Air Command (SAC) was a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile compon ...
to get its active aircraft airborne long before Soviet bombers could reach their targets. The need was considered critical and the construction was given the highest national priorities. Advance site preparation began in December 1954, and the construction was carried out in a massive logistical operation that took place mostly during the summer months when the sites could be reached by ships. The 63-base line reached operational status in 1957. The MCL was shut down in the early 1960s, and much of the Pinetree Line was given over to civilian use. In 1985, as part of the " Shamrock Summit", the United States and Canada agreed to transition DEW to the new North Warning System (NWS). Beginning in 1988, most of the original DEW stations were deactivated, while a small number were upgraded with all-new equipment. The official handover from DEW to NWS took place on 15 July 1993.


Introduction

The shortest, or
great circle In mathematics, a great circle or orthodrome is the circular intersection of a sphere and a plane passing through the sphere's center point. Discussion Any arc of a great circle is a geodesic of the sphere, so that great circles in spher ...
, route for a Soviet air attack on North America was through the Arctic, across the area around the
North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...
. The DEW Line was built during the
Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
to give early warning of a Soviet nuclear strike, to allow time for United States bombers to get off the ground and land-based
intercontinental ballistic missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
(ICBMs) to be launched, to reduce the chances that a preemptive strike could destroy the United States' strategic nuclear forces. The original DEW line was designed to detect bombers and was unable to detect ICBMs. To give warning of this threat, in 1958 a more sophisticated radar system was constructed, the Ballistic Missile Early Warning System (BMEWS). The DEW Line was a significant achievement among Cold War initiatives in the Arctic. A successful combination of scientific design and logistical planning of the late 1950s, the DEW Line consisted of a string of continental defence radar installations, ultimately stretching from Alaska to Greenland. In addition to the secondary Mid-Canada Line and the tertiary Pinetree Line, the DEW Line marked the edge of an electronic grid controlled by the new
Semi-Automatic Ground Environment The Semi-Automatic Ground Environment (SAGE) was a system of mainframe computer, large computers and associated computer network, networking equipment that coordinated data from many radar sites and processed it to produce a single unified image ...
(SAGE) computer system and was ultimately centred at the
Cheyenne Mountain Complex The Cheyenne Mountain Complex is a United States Space Force installation and defensive bunker located in unincorporated El Paso County, Colorado, next to the city of Colorado Springs, at the Cheyenne Mountain Space Force Station, which host ...
,
Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...
, command hub of the
North American Aerospace Defense Command North American Aerospace Defense Command (NORAD ; , CDAAN), known until March 1981 as the North American Air Defense Command, is a Combined operations, combined organization of the United States and Canada that provides aerospace warning, air ...
(NORAD). The construction of the DEW Line was made possible by a bilateral agreement between the Canadian and United States governments, and by collaboration between the
United States Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an United States federal executive departments, executive department of the federal government of the United States, U.S. federal government charged with coordinating and superv ...
and the
Bell System The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the AT&T Corporation, American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America fo ...
of communication companies. The DEW Line grew out of a detailed study made by a group of the nation's foremost scientists in 1952, the Summer Study Group at the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
. The subject of the study was the vulnerability of the United States and Canada to aerial bombing attacks, and its concluding recommendation was that a ''distant early warning line'' of search radar stations be built across the Arctic region of the North American continent as rapidly as possible.


Development and construction

Improvements in Soviet technology rendered the Pinetree Line and Mid-Canada Line inadequate to provide enough early warning and on 15 February 1954, the Canadian and United States governments agreed to jointly build a third line of radar stations (Distant Early Warning), this time running across the high Arctic. The line would run roughly along the 69th parallel north, about north of the
Arctic Circle The Arctic Circle is one of the two polar circles, and the northernmost of the five major circle of latitude, circles of latitude as shown on maps of Earth at about 66° 34' N. Its southern counterpart is the Antarctic Circle. The Arctic Circl ...
. Before this project was completed, men and women with the necessary knowledge, skills, and experience were drawn from Bell Telephone companies in every state in the United States, and many Canadian provinces. Much of the responsibility was delegated under close supervision to a vast number of subcontractors, suppliers, and United States military units. The initial contract with the
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
and the
Royal Canadian Air Force The Royal Canadian Air Force (RCAF; ) is the air and space force of Canada. Its role is to "provide the Canadian Forces with relevant, responsive and effective airpower". The RCAF is one of three environmental commands within the unified Can ...
provided for the design and construction of a small experimental system to determine at the beginning whether the idea was practicable. The designs of communication and radar detection equipment available at the time were known to be unsuited to the weather and atmospheric conditions to be encountered in the Arctic. Early efforts were aided when, by happenstance, the US Navy terminated its oil exploration activities in Alaska. The associated infrastructure that had been established in the arctic was quickly repurposed to serve early development of the DEW line. Material converted from Navy use included 1,200 tons of supplies, with many Caterpillar D8 tractors, heavy duty cranes, diesel generators, and radio equipment. Most fortunately, the surplus included sixty equipped wannigans - enough to permit setup of field camps at all construction sites. (A "wannigan" is a building on sleds, about 12 x 20 feet in size. These were completely equipped for camp operations and were of various types - Cook, Mess, Bunk, Power Plant, Water, Shop, Storage, Utility, Steam Point, etc.) Prototypes of several stations were designed and built in
Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
in 1953. A prototype built for training purposes was chosen to be located in
Streator, Illinois Streator is a city in LaSalle County, Illinois, LaSalle and Livingston County, Illinois, Livingston counties in the U.S. state of Illinois. The city is situated on the Vermilion River (Illinois River tributary), Vermilion River approximately so ...
in 1952. The Streator DEW-Line Training Center became operational in 1956 and closed when operations were moved to
Colorado Springs, Colorado Colorado Springs is the most populous city in El Paso County, Colorado, United States, and its county seat. The city had a population of 478,961 at the 2020 United States census, 2020 census, a 15.02% increase since 2010 United States Census, 2 ...
in 1975. While few of the original designs for either buildings or equipment were retained, the trial installations did prove that the DEW Line was feasible, and they furnished a background of information that led to the final improved designs of all facilities and final plans for manpower, transportation, and supply. With the experimental phase completed successfully, the Air Forces asked the
Western Electric Company Western Electric Co., Inc. was an American electrical engineering and manufacturing company that operated from 1869 to 1996. A subsidiary of the AT&T Corporation for most of its lifespan, Western Electric was the primary manufacturer, supplier, ...
to proceed as rapidly as possible with the construction of the entire DEW Line. That was in December 1954, before the route to be followed in the eastern section had even been determined. The locations were surveyed out by John Anderson-Thompson. Siting crews covered the area – first from the air and then on the ground – to locate by scientific means the best sites for the main, auxiliary, and intermediate stations. These crews lived and worked under primitive conditions. They covered vast distances by airplanes,
snowmobile A snowmobile, also known as a snowmachine (chiefly Alaskan), motor sled (chiefly Canadian), motor sledge, skimobile, snow scooter, or simply a sled is a motorized vehicle designed for winter travel and recreation on snow. Their engines normally ...
s, and
dog sled A dog sled or dog sleigh is a sled pulled by one or more sled dogs used to travel over ice and through snow, a practice known as mushing. Numerous types of sleds are used, depending on their function. They can be used for Sled dog racing, dog sl ...
s, working in blinding snowstorms with temperatures so low that ordinary thermometers could not measure them. They completed their part of the job on schedule and set the stage for the crews and machines that followed. The line consisted of 63 stations stretching from Alaska to
Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada, the second-largest island in the Americas (behind Greenland), and the fifth-largest island in the world. Its area is (slightly smal ...
, covering nearly . The United States agreed to pay for and construct the line, and to employ Canadian labour as much as possible. A target date for completing the DEW Line and having it in operation was set for 31 July 1957. This provided only two short Arctic summers adding up to about six months in which to work under passable conditions. Much of the work would have to be completed in the long, dark, cold, Arctic winters, including over a month of
polar night Polar night is a phenomenon that occurs in the polar regions of Earth, northernmost and southernmost regions of Earth when the Sun remains below the horizon for more than 24 hours. This only occurs inside the polar circles. The opposite phen ...
.


Construction process

From a standing start in December 1954, many thousands of skilled workers were recruited, transported to the polar regions, housed, fed, and supplied with tools, machines, and materials to construct physical facilities – buildings, roads, tanks, towers, antennas, airfields, and hangars – in some of the most hostile and isolated environments in North America. The construction project employed about 25,000 people. Western Electric and Alaska Freightlines, with the help of the
United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...
Transportation Research and Development Command (TRADCOM), contracted to have a pair of off-road overland trains, the TC-264 Sno-Buggy, designed specifically for Arctic conditions, to be built by LeTourneau Technologies, owned by R. G. LeTourneau. The TC-264 Sno-Buggy was the longest off-road vehicle ever built at the time, with its six cars (including the locomotive) measuring a total of . Each car was driven by four tall wheels and tires. The 24-wheel-drive was powered by two 400 horsepower
Cummins Cummins Inc. is an American multinational corporation, multinational corporation that designs, manufactures, and distributes engines, electric vehicle components, and power generation products. Cummins also services engines and related equipmen ...
diesel engines connected to a hub motor. It had a payload capacity of , and could traverse nearly any terrain. It had a very successful first season hauling freight to the DEW Line. Later, military and civilian airlifts, huge
sealift Sealift is a term used predominantly in military logistics and refers to the use of cargo ships for the deployment of military assets, such as weaponry, vehicles, military personnel, and supplies. It complements other means of transport, such as ...
s during the short summers, barges contributed to the distribution of vast cargoes along the length of the Line to build the permanent settlements needed at each site. Much of the job of carrying mountains of supplies to the northern sites fell to military and naval units. More than 3,000 United States Army Transportation Corps soldiers were given special training to prepare them for the job of unloading ships in the
Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
. They went with the convoys of
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
ships and they raced time during the few weeks the ice was open to land supplies at dozens of spots on the shores of the
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...
during the summers of 1955, 1956, and 1957. Scores of military and commercial pilots, flying everything from small bush planes to four-engined
turboprop A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, compressor, combustor, turbine, and a propellin ...
s, were the backbone of the operation. The Lockheed LC-130, a ski-equipped version of the
C-130 Hercules The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built by Lockheed Corporation, Lockheed (now Lockheed Martin). Capable of using unprepared runways for takeoffs and landings, the C-130 w ...
, owned by the United States Air Force and operated by the 139th Airlift Squadron, provided a significant amount of airlift to sites that were out on
ice cap In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses covering more than are termed ice sheets. Description By definition, ice caps are not constrained by topogra ...
s such as Dye 3 in Greenland. Transport planes such as the
C-124 Globemaster The Douglas C-124 Globemaster II, nicknamed "Old Shaky", is a retired American heavy-lift cargo aircraft built by the Douglas Aircraft Company in Long Beach, California. The C-124 was the primary heavy-lift transport for United States Air Forc ...
and the C-119 Flying Boxcar also supported the project. Together, these provided the only means of access to many of the stations during the wintertime. In all, of materials were moved from the United States and southern Canada to the Arctic by air, land, and sea. As the stacks of materials at the station sites mounted, construction went ahead rapidly. Subcontractors with a flair for tackling difficult construction projects handled the bulk of this work under the direction of Western Electric engineers. Huge quantities of gravel were produced and moved. The construction work needed to build housing, airstrips, aircraft
hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...
s, outdoor and covered antennas, and antenna towers was done by subcontractors. In all, over 7,000
bulldozer A bulldozer or dozer (also called a crawler) is a large tractor equipped with a metal #Blade, blade at the front for pushing material (soil, sand, snow, rubble, or rock) during construction work. It travels most commonly on continuous tracks, ...
operators, carpenters, masons, plumbers, welders, electricians, and other tradesmen from the United States and southern Canada worked on the project. Concrete was poured in the middle of Arctic winters, buildings were constructed, electrical service, heating, and fresh water were provided, huge steel antenna towers were erected, airstrips and hangars were built, putting it all together in darkness, blizzards, and subzero temperatures. After the buildings came the installation of radar and communications equipment, then the thorough and time-consuming testing of each unit individually and of the system as an integrated whole. Finally all was ready, and on 15 April 1957 – just two years and eight months after the decision to build the Distant Early Warning Line was made – Western Electric turned over to the Air Force on schedule a complete, operating radar system across the top of North America, with its own communications network. Later, the system coverage was expanded even further: see Project Stretchout and Project Bluegrass. The majority of Canadian DEW Line stations were the joint responsibility of the Royal Canadian Air Force (the
Canadian Armed Forces The Canadian Armed Forces (CAF; , FAC) are the unified Military, military forces of Canada, including sea, land, and air commands referred to as the Royal Canadian Navy, Canadian Army and the Royal Canadian Air Force. Under the ''National Defenc ...
) and the United States Air Force. The USAF component was the 64th Air Division,
Air Defense Command Aerospace Defense Command was a major command (military formation), command of the United States Air Force, responsible for air defense of the continental United States. It was activated in 1968 and disbanded in 1980. Its predecessor, Air De ...
. The 4601st Support Squadron, based in
Paramus, New Jersey Paramus ( Waggoner, Walter H, ''The New York Times'', February 16, 1966. Accessed October 16, 2018. "Paramus – pronounced puh-RAHM-us, with the accent on the second syllable – may have taken its name from 'perremus' or 'perymus,' Indian for ...
, was activated by ADC to provide logistical and contractual support for DEW Line operations. In 1958, the line became a cornerstone of the new North American Aerospace Defense Command (NORAD) organization of joint continental
air defence Anti-aircraft warfare (AAW) is the counter to aerial warfare and includes "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It encompasses surface-based, subsurface (Submarine#Armament, submarine-lau ...
. USAF personnel were limited to the main stations for each sector and they performed annual inspections of auxiliary and intermediate stations as part of the contract administration. Most operations were performed by Canadian and United States civilian personnel, and the operations were automated as much as was possible at the time. All of the installations flew both the Canadian and United States flags until they were deactivated as DEW sites and sole jurisdiction was given to the
Government of Canada The Government of Canada (), formally His Majesty's Government (), is the body responsible for the federation, federal administration of Canada. The term ''Government of Canada'' refers specifically to the executive, which includes Minister of t ...
as part of the North Warning System in the late 1980s and early 1990s.


Radar system

The Point Lay, Alaska DEW line station has a typical suite of systems. The main
AN/FPS-19 The AN/FPS-19 was a long-range search radar developed for the NORAD Distant Early Warning Line (DEW Line) by Raytheon. It was an L-band system working between 1220 and 1350 MHz produced by a 500 kW magnetron. Two such systems were pla ...
search radar is in the dome, flanked by two AN/FRC-45 lateral communications dishes (or AN/FRC-102, depending on the date). To the left are the much larger southbound AN/FRC-101 communications dishes. Not visible is the AN/FPS-23 "gap filler" doppler antenna. The DEW Line was upgraded with fifteen new AN/FPS-117 passive electronically scanned array radar systems between 1985 and 1994, and the line was then renamed the North Warning System. :Operating characteristics of the AN/TPS-1D (Mod c) search radar * Frequency range 1.22 to 1.35
GHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...
* Peak power output 160 kilowatts Average power output 400 watts * Pulse rate 400 pulses per second ** Pulse width 6.0 microsecond * Range to * Antenna radiation pattern ** Horizontal 2.8-degree ** Vertical 30 deg cosecant2 (elevation angle) * Receiver noise figure 11.7 dB * IF bandwidth and frequency 5.0 MHz and 60 MHz * Required prime power 8.5 kW * Weight of radar about * Total volume of radar electronics about Modifications to each operating radar station occurred during the construction phase of the DEW Line system. This was due to the extreme winds, frigid temperatures, and the ground conditions due to
permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...
and ice. There were two significant electronic modifications that were also crucial to the functioning of these radar stations in an Arctic environment. One reduced the effects of vibration in correlation to temperature change, the other increased the pulse duration from two to six microseconds. It also began using a
crystal oscillator A crystal oscillator is an electronic oscillator Electrical circuit, circuit that uses a piezoelectricity, piezoelectric crystal as a frequency selective surface, frequency-selective element. The oscillator frequency is often used to keep trac ...
for more stable readings and accurate accounts of movement within the air.


Operations

There were three types of stations: small unstaffed "gap filler stations" that were checked by ground crews only every few months during the summer; intermediate stations with only a station chief, a cook, and a mechanic; and larger stations that had a variable number of employees and may have had libraries, forms of entertainment, and other accommodations. The stations used a number of long-range L band – emitting systems known as the AN/FPS-19. The "gaps" between the stations were watched by the directional AN/FPS-23
doppler radar A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the fre ...
systems, similar to those pioneered only a few years earlier on the Mid-Canada Line. The stations were interconnected by White Alice, a series of radio communications systems that used tropospheric scatter technology. For stations at the western end of the line, buildings at the deactivated Pet-4 United States Navy camp at Point Barrow were converted into workshops where prefabricated panels, fully insulated, were assembled to form modular building units long, wide, and high. These modules were put on sleds and drawn to station sites hundreds of miles away by powerful tractors. Each main station had its own airstrip – as close to the buildings as safety regulations and the terrain permitted. Service buildings, garages, connecting roads, storage tanks, and perhaps an aircraft hangar completed the community. Drifting snow was a constant menace. Siting engineers and advance parties learned this the hard way when their tents disappeared beneath the snow in a few hours. The permanent H-shaped buildings at the main stations were always pointed into the prevailing winds and their bridges built high off the ground. The Arctic region was frequently transited by commercial aircraft on polar routes, either flying between Europe and western North America, or between Europe and Asia using Alaska as a stopover. These flights would penetrate the DEW Line. To differentiate these commercial flights from Soviet bombers, the flight crews had to transmit their flight plan to an Air Movement Identification System (AMIS) centre at either Goose Bay,
Edmonton Edmonton is the capital city of the Provinces and territories of Canada, Canadian province of Alberta. It is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Central Alberta ...
, or
Anchorage Anchorage, officially the Municipality of Anchorage, is the most populous city in the U.S. state of Alaska. With a population of 291,247 at the 2020 census, it contains nearly 40 percent of the state's population. The Anchorage metropolita ...
. These stations then passed the information on to the DEW Line.A History of the DEW Line, Aerospace Defense Command Historical Study No. 31, SECRET, June 1965.
/ref> If an unknown flight was detected, the DEW Line station would contact AMIS to see if a flight plan might have been missed; if not, NORAD was notified. Military flights, including B-52 bombers, frequently operated in the polar regions and used
identification friend or foe Identification, friend or foe (IFF) is a combat identification system designed for command and control. It uses a transponder that listens for an ''interrogation'' signal and then sends a ''response'' that identifies the broadcaster. IFF syst ...
(IFF) systems to authenticate the flight. The early warning provided was useless against ICBMs and
submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...
-launched attacks. These were countered and tempered by the
mutual assured destruction Mutual assured destruction (MAD) is a doctrine of military strategy and national security policy which posits that a full-scale use of nuclear weapons by an attacker on a nuclear-armed defender with second-strike capabilities would result in ...
(MAD) philosophy. However, the scenario of a coordinated airborne invasion coupled with a limited nuclear strike was the real threat that this line protected against. It did so by providing Distant Early Warning of an inbound aerial invasion force, which would have to appear at the far north hours ahead of any warhead launches in order to be coordinated well enough to prevent MAD. A number of intermediate stations were decommissioned, since their effectiveness was judged to be less than desired and required. The staffed stations were retained to monitor potential Soviet air activities and to allow Canada to assert sovereignty in the Arctic. International law requires a country that claims territory to actively occupy and defend such territory. Because the advent of ICBMs created another attack scenario that the DEW Line could not defend against, in 1958 the
United States Federal Government The Federal Government of the United States of America (U.S. federal government or U.S. government) is the Federation#Federal governments, national government of the United States. The U.S. federal government is composed of three distinct ...
authorized construction of the Ballistic Missile Early Warning System (BMEWS), at a reported cost of $28 billion. In 1985, it was decided that the more capable of the DEW Line stations were to be upgraded with the GE AN/FPS-117 radar systems and merged with newly built stations into the North Warning System. Their automation was increased and a number of additional stations were closed. This upgrading was completed in 1990, and with the end of the Cold War and
dissolution of the Soviet Union The Soviet Union was formally dissolved as a sovereign state and subject of international law on 26 December 1991 by Declaration No. 142-N of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. Declaration No. 142-Н of ...
, the United States withdrew all of its personnel and relinquished full operation of the Canadian stations to Canada. Costs for the Canadian sector were still subsidized by the United States. However, the American flags were lowered at the Canadian stations and only the Canadian flag remained. The United States retained responsibility and all operational costs for North Warning System stations located in Alaska and Greenland.


Canadian perception

From the beginning of the development of the DEW Line idea, Canadian concerns over political perception grew enormously. Noted
Canadian Arctic Northern Canada (), colloquially the North or the Territories, is the vast northernmost region of Canada, variously defined by geography and politics. Politically, the term refers to the three territories of Canada: Yukon, Northwest Territories a ...
historian P. Whitney Lackenbauer argues that the Canadian Government saw little intrinsic value in the Arctic, but due to fear of Americanization and American penetration into the Canadian Arctic, brought significant changes and a more militaristic role to the north. This shift into a more military role began with a transition of authority, shifting responsibility of Arctic defence in Canada from the
Royal Canadian Mounted Police The Royal Canadian Mounted Police (RCMP; , GRC) is the Law enforcement in Canada, national police service of Canada. The RCMP is an agency of the Government of Canada; it also provides police services under contract to 11 Provinces and terri ...
to the Canadian Armed Forces. This "active defence" had three key elements: minimizing the extent of the American presence in the Canadian Arctic, Canadian government input into the management of the DEW Line, and full Canadian participation in Arctic defence. Funding problems for the DEW Line also played a role in perception of the project. American investment in building and operating the DEW Line system declined as the ICBM threat refocused priorities, but Canada did not fill the void with commensurate additional funding. In 1968 a Canadian Department of National Defence Paper (27 November 1968) stated no further funding for research on the DEW Line or air space would be allocated due in part to lack of commercial activity The Canadian Government also limited United States air activity, base activity, soldier numbers, and contractor numbers; and the overall operation would be considered and called in all formalities a "joint operation".


Cultural impact

The cultural impact of the DEW Line System is immense in Canada and Alaska. In Canada, the DEW line increased connections between the populous south and the remote High Arctic, helping to bring
Inuit Inuit (singular: Inuk) are a group of culturally and historically similar Indigenous peoples traditionally inhabiting the Arctic and Subarctic regions of North America and Russia, including Greenland, Labrador, Quebec, Nunavut, the Northwe ...
more thoroughly into the Canadian polity. The construction and operating of the DEW Line provided some economic development for the Arctic region. This provided momentum for further development through research, new communications, and new studies of the area. Although the construction of the DEW line itself was placed in American hands, much of the later development was under direct Canadian direction. What to do with historical DEW Line sites is currently under discussion in Canada and Alaska. The discussion stems from the deactivation aspect of the sites and arguments over what to do with leftover equipment and leftover intact sites. Many Canadian historians encourage the preservation of DEW Line sites through heritage designations. The DEW Line is a setting for the 1957 film '' The Deadly Mantis''. The film begins with a short documentary on the three RADAR lines, focusing on the DEW Line's construction. The progressive rock band Rush received considerable AOR airplay in 1984 with their song Distant Early Warning, based on a Toronto newspaper article expressing concerns about risk of nuclear war.


Deactivation and clean-up

In 1996, the United States Government entered into an agreement with the Government of Canada on the environmental remediation of the DEW Line Sites in Canada, alongside the remediation of the Haines-Fairbanks Pipeline, Naval Station Argentia in
Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...
, and U.S. installations at CFB Goose Bay in
Labrador Labrador () is a geographic and cultural region within the Canadian province of Newfoundland and Labrador. It is the primarily continental portion of the province and constitutes 71% of the province's area but is home to only 6% of its populatio ...
. While asserting it had no legal obligation to reimburse Canada for the costs of remediation, the U.S. agreed to deposit US$100 million () into Canada's
Foreign Military Sales Foreign Military Sales (FMS) is a security assistance program of the United States government to facilitate the purchase of U.S. arms, defense equipment, design and construction services, and military training to foreign governments. FMS is a gove ...
Trust Account as compensation for the costs of cleanup of the four projects. The cleanup is now underway, site by site. In assessing the cleanup, new research suggests that off-road vehicles damaged vegetation and organic matter, resulting in the melting of the permafrost, a key component to the
hydrological Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...
systems of the areas.Lackenbauer, Whitney P. "The Cold War on Canadian Soil: Militarizing a Northern Environment." American Society for Environmental History, Vol. 12, No. 4. Special Issue on Canada (Oct 2007), 932. The DEW Line has also been linked to depleted fish stocks and carelessness in agitating local animals such as the
caribou The reindeer or caribou (''Rangifer tarandus'') is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, boreal, and mountainous regions of Northern Europe, Siberia, and North America. It is the only represe ...
, as well as non-seasonal hunting. These aspects are claimed to have had a devastating impact on the local native subsistence economies and environment.


Atlantic and Pacific Barrier

The DEW line was supplemented by the Contiguous Radar Coverage System, which included two "barrier" forces in the Atlantic and the Pacific oceans which were operated by the United States Navy from 1956 to 1965. These barrier forces consisted of surface picket stations, dubbed "
Texas Towers Texas Towers were a set of three radar facilities off the eastern seaboard of the United States which were used for surveillance by the United States Air Force during the Cold War. Modeled on the offshore oil drilling platforms first employed off ...
", a surface naval force of 12
radar picket A radar picket is a radar-equipped station, ship, submarine, aircraft, or vehicle used to increase the radar detection range around a nation or military (including naval) force to protect it from surprise attack, typically air attack, or from c ...
destroyer escorts and 16 Guardian-class radar picket ships, and an air wing of Lockheed WV-2 Warning Star aircraft that patrolled the picket lines at an altitude of in 12- to 14-hour missions. Their objective was to extend early warning coverage against surprise Soviet bomber and missile attack as an extension of the DEW Line.Bouchard, Capt. Joseph F. (USN)
"Guarding the Cold War Ramparts."
''dean-boys.com''. Retrieved: 13 March 2009.
The Atlantic Barrier (BarLant) consisted of two rotating squadrons, one based at Naval Station Argentia,
Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...
, to fly orbits to the Lajes Field in the
Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...
and back; and the other at Naval Air Station Patuxent River, Maryland. BarLant began operations on 1 July 1956, and flew continuous coverage until early 1965, when the barrier was shifted to cover the approaches between Greenland, Iceland, and the United Kingdom ( GIUK barrier). Aircraft from Argentia were staged through Naval Air Station Keflavik, Iceland, to extend coverage times. The Pacific Barrier (BarPac) began operations with one squadron operating from
Naval Air Station Barbers Point Naval Air Station Barbers Point , on O'ahu, home to John Rodgers (naval officer, World War I), John Rodgers Field (the original name of Honolulu International Airport), is a former United States Navy airfield closed in 1999, and renamed Kalaeloa ...
, Hawaii, and a forward refuelling base at Naval Air Facility Midway Island, on 1 July 1958. Planes flew from Midway Island to Naval Air Facility Adak on Adak Island (in the Aleutian Island chain) and back, non-stop. Its orbits overlapped the radar picket stations of the ships of Escort Squadron Seven (CORTRON SEVEN), from roughly Kodiak Island to the
Midway Atoll Midway Atoll (colloquialism, colloquial: Midway Islands; ; ) is a atoll in the North Pacific Ocean. Midway Atoll is an insular area of the United States and is an Insular area#Unorganized unincorporated territories, unorganized and unincorpo ...
and Escort Squadron Five (CORTRON FIVE), from
Pearl Harbor Pearl Harbor is an American lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. It was often visited by the naval fleet of the United States, before it was acquired from the Hawaiian Kingdom by the U.S. with the signing of the Reci ...
to northern Pacific waters. Normally four or five WV-2s were required at any single time to provide coverage over the entire line. This coverage was later augmented, and modified/replaced by Project Stretchout and Project Bluegrass). The ''Guardian''-class radar picket ships were based in
Rhode Island Rhode Island ( ) is a state in the New England region of the Northeastern United States. It borders Connecticut to its west; Massachusetts to its north and east; and the Atlantic Ocean to its south via Rhode Island Sound and Block Is ...
and
San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...
, and covered picket stations off each coast. Barrier Force operations were discontinued by September 1965 and their EC-121K (WV-2 before 1962) aircraft placed in storage.


See also

* DYE Stations, the DEW line extension to Iceland * List of DEW Line Sites * List of Royal Canadian Air Force stations * List of Canadian Forces bases * Main Centre for Missile Attack Warning * North Atlantic Radio System, communication system similar to White Alice for the DYE Stations and others stretching to the UK


References


External links


DEW Line Story video

Big Picture: DEW Line video
{{Authority control Royal Canadian Air Force Air defence radar networks Cold War military history of Canada Canada–United States military relations Radar stations of the United States Air Force Military globalization Military in the Arctic