It is worth comparing BRAVO to the most powerful nuclear test ever, the Soviet Union's 50-megaton "Tsar Bomba" of 30 October 1961. That test's radiological consequences were far less severe because the "Tsar Bomba's" fireball never touched the earth's surface producing significantly less fallout than BRAVO.
http://www2.gwu.edu/~nsarchiv/nukevault/ebb459/