Originates from African cultures. Boo-yaa was a soup BASE made for leftover foods.
In the 80's and 90's a mixture of free BASE cocaine, the residuals found at the bottom of the screen, and the resin from the pipe collected together- a collection of leftovers - was smoked. The smoker would then exhale and exclaim, "boo-yaa"
We knew he got a good hit when he exclaimed, "boo-yaa".