Operation Distant Plain


Operation Distant Plain was a series of non-nuclear explosive and detonable gas tests performed on test sites in Alberta, Canada during the course of 1966 and 1967. Their purpose was to provide airblast, cratering and ground shock data in summer and winter conditions for testing new prototype equipment, military targets and coniferous forest blowdown and defoliation. Participants included Canada, United Kingdom, Australia and United States under the Tripartite Technical Cooperation Program. Detonable gas balloons were used in this operation in an attempt to find an economical substitute for TNT as well as for the fact that they could be placed at desired heights without a heavy support structure or towers. In addition, they were more adaptable to airblast phenomena and produced a well defined blast wave without perturbation or ejecta; they also produced no crater. However, it was found that they lacked the high pressure associated with high explosives, and difficulties were encountered as the 20-ton gas balloon ruptured and another detonated unexpectedly during inflation. Ultimately ANFO was elected as a lower cost alternative to TNT for non-nuclear explosives tests.

Tests

The following table summarizes the events that took place during the operation in chronological order.
EventDateChargeYield Height of Burst LocationNotes
17 July 1966TNT sphere, tower2085Drowning Ford Test Range, SESAirblast and induced ground motions
2July 1966125 foot methane-oxygen balloon2085Drowning Ford Test Range, SESCancelled, balloon ruptured during inflation
2A22 July 1966125 foot propane-oxygen hemisphere200Drowning Ford Test Range, SESTest feasibility of detonable gas, compare with 20 ton TNT events
327 July 1966TNT sphere, half buried200Drowning Ford Test Range, SESNormal environment control for Event 5
416 August 1966TNT Hemisphere500Edson Forest, 10 miles northwest of HintonConiferous forest blowdown test
2BOctober 1966125 foot methane-oxygen balloon18.663Drowning Ford Test Range, SESRescheduled Event 2, detonated unexpectedly during inflation on ground
59 February, 1967TNT sphere, half buried200Drowning Ford Test Range, SESFrozen ground test
626 July 1967TNT sphere, supported1000Watchdog Hill Blast Range, SESNuclear weapon surface burst simulation
1A18 August 1967TNT sphere, tower2030Watchdog Hill Blast Range, SESAirblast and induced ground motions, repeat of event 1