Canada and Special Weather Intelligence

In the era before weather satellites, access to information about weather conditions in adversary-controlled areas could be highly valuable. Such information could be used to determine the likelihood of hostile military activities in those areas, to support friendly military activities in or near those areas, and to provide data for future weather forecasts in other parts of the region. Since weather data was often sent to adversary military forces as part of their routine encrypted communications, such information could also provide a "probable plain text" clue that might prove useful in breaking into certain of those encryption systems.

For these reasons, during the Second World War and the Cold War, reports from adversary weather stations were themselves often encrypted, and they were the target of SIGINT collection and codebreaking activities. Within the UKUSA community, intelligence derived from collection of weather station reports was known as Special Weather Intelligence.

The Friedman documents released by the NSA earlier this year contain some interesting insight into Canada's access to Special Weather Intelligence related to the Far East acquired by NSA and GCHQ.

This document reports that although Canada did not originally foresee a need for more than Summaries of such material,

On 23 December 1953, Hq, USAF, Directorate of Intelligence (a) informed [NSA] that the RCAF is ready to receive such [redacted] as is now available from the [redacted], and (b) suggested that the Director, NSA, make arrangements with the RCAF to furnish materials to RCAF Headquarters via the NSA/CBNRC communications link. Accordingly, arrangements have been completed for this channel to be used carrying information prepared by [redacted] from the products of the [redacted.] It would appear that the Canadian requirements for codeword [redacted] have expanded beyond [redacted] Summaries.

The parts of the document that confirm that the subject of this discussion was Special Weather Intelligence have all been redacted, unfortunately, but this other Friedman document helpfully fills in the most important blank, informing us that the title of the first document is "US/UK/CAN Tripartite Arrangements Concerning Far East Special Weather Intelligence" (see entry for USCIB 1.1/1 on page 62).

And these two documents confirm that

On 15 May 1954, LSIB, CRC and USCIB recognized that Canada's peacetime requirements for [redacted] Intelligence bearing codewords had increased subsequent to the Tripartite Conference of March 1953. LSIB, CRC and USCIB therefore agreed that such codeword materials as are required by any of the three parties should be requested under the regular procedures already established for requesting all other types of COMINT codeword material.

(LSIB, CRC, and USCIB were the London Signals Intelligence Board, the Communications Research Committee, and the United States Communications Intelligence Board, the U.K., Canadian, and U.S. interdepartmental committees respectively in charge of GCHQ, CBNRC, and NSA.)

It is interesting to speculate about what may have changed between March 1953 and December 1953 to cause Canada, and the RCAF in particular, to require greater access to Far East Special Weather Intelligence.

Canadian Army and Royal Canadian Navy units took part in the Korean War, and RCAF transport aircraft operated between North America and Korea during the war, but the fighting had been over for nearly five months by the time the RCAF reported it was "ready to receive" expanded access, and by nearly ten months by the time the expanded access actually began. Furthermore, the tripartite statement approving that expanded access described it explicitly as a "peacetime" requirement. It seems highly unlikely, therefore, that the RCAF's need was related to the Korean War.

One possibility is that the RCAF wanted access to the information to help it plan North American early warning and air defence operations with the USAF. (The Far East includes the eastern part of the Soviet Union, which would have been the source of many of the aircraft taking part in an attack on North America.)

Another possibility is that the RCAF wanted the data in support of its own planned operations in the Arctic. In September 1953, the RCAF decided to convert three photo reconnaissance/aerial mapping variants of the Lancaster bomber to an Arctic reconnaissance configuration. According to one source, some of the missions flown by the aircraft involved "ECM patrol in the ocean area well north of the Queen Elizabeth Archipelago, carrying out a listening watch for Soviet electronic emissions." The first mission with the newly converted aircraft was flown in September 1954.

Neither theory (air defence or Arctic reconnaissance) explains why the RCAF's request was limited specifically to Far East Special Weather Intelligence, however. Perhaps Canada already had access to weather intelligence for other regions in the North.

This webpage on the Soviet M-130 Koralle encryption machine discusses the use of encryption for Soviet and Soviet Bloc weather data. However, according to the authors, the M-130 was introduced in 1965, so evidently this machine was not used during the 1950s.


Update 1 January 2016: For more on weather intelligence, see Jeffrey T. Richelson, "Weather or Not," Air Force Magazine, October 2013.