Wahoo and Umbrella were both underwater nuclear test conducted in the waters off Enewetak Atoll in the Pacific Ocean in May and June of 1958. Wahoo was a deepwater test at 3200 ft. and Umbrella was a shallow water test at 150 ft. This is a declassified video which is narrated by a cameraman, but it is not specified which test is occurring in this video.
"Beneath this concrete dome (referred to as the Cactus Dome) on Runit Island, part of Enewetak Atoll between 1977 and 1980 at a cost of about $239 million, lie 111 000 cubic yards of radioactive soil and debris from Bikini and Rongelap Atolls. The dome covers the 30-foot deep, 350-foot wide crater created by the May 5, 1958, Cactus test." -Brooklyn Institute
The Enewetak Atoll had been inhabited by humans for more then 2000 years, but after WWII the Americans gained control of the series of Islands from the Japanese and in the early 1950's forced the inhabitants off the islands while conducting 43 nuclear tests within the next decade. In the early 1980's the inhabitants were aloud to return and in 1986 they received their independence. In 2000, the Marshall Islands Claims Tribunal awarded in excess of $340 million to the people of Enewetak for loss of use, hardship, medical Difficulties and further nuclear cleanup.