http://abcnews.go.com/US/story?id=1788259
"A Pentagon test at a Nevada site this June will likely create the first mushroom cloud seen in the state since the United States ceased above-ground nuclear testing in 1963.
Mushroom clouds are commonly associated with nuclear blasts, but this cloud will come from the detonation of a 700-ton explosive charge designed to test new bunker-busting technologies."
"The Defense Threat Reduction Agency hopes the test — called Divine Strake — will help with the effort to develop weapons that can destroy deep underground bunkers storing nuclear, chemical or biological weapons."
"the test is planned for June"