The Russian navy in late 2019 surged a huge number of submarines into the Atlantic Ocean, prompting NATO to sortie patrol planes from Norway, Iceland and Scotland.
The result was one of the biggest concentrations in years of submarines and anti-submarine-warfare aircraft. And a stark reminder that NATO and Russian naval and air activity is returning to Cold War-levels of intensity.
The Russian navy in mid-October 2019 deployed submarines in the country’s biggest undersea exercise since the Cold War.
The eight subs, including six nuclear-powered boats, sailed from their bases in northern Russia into the cold waters of the Barents and Norwegian Seas.
At the same time, an additional two boats -- the nuclear-powered Sierra-class attack submarines Pskov and Nizhny Novgorod -- sailed into roughly the same waters for tests and training.
The 10 vessels represent around 20 percent of the Russian submarine force.
More than a dozen NATO patrol planes flew back-to-back missions in order to find and track Moscow’s submarines. Amatuer plane-spotters using commercial software kept tabs on the planes’ transponders.
It’s unclear how many NATO submarines also joined the hunt for the Russian boats.
Between Oct. 25 and Nov. 7, 2019, the NATO planes flew more than 40 missions. Six Norwegian air force P-3s, four U.S. Navy P-8s and a Canadian air force CP-140 flew from Andoya in Norway. At least one additional P-8 flew from Keflavik in Iceland. A French navy Atlantic 2 patroller staged from Prestwick airport in Scotland.
Flight-trackers followed the patrol planes as they flew hundreds of miles into the North Atlantic to fly racetrack patterns over the apparent locations of Russian submarines. The patrol planes use their radars, sonar buoys and magnetic detectors to find subs on and below the waves.
The submarine activity, and anti-submarine patrols, appeared to concentrate on the eastern side of the so-called “GIUK Gap,” the stretches of open ocean between Greenland, Iceland and the United Kingdom.