A Russian or other women of eastern European ethnicity, who will undoubtedly explode when they reach the pre-designated genetic time frame. The latter usually being ages 40+ but there are reported incidents of this happening as young as 30 or even sooner if they have children. This explosion is what constitutes them as a Russian Time-bomb. The young beautiful Russian women will transform into the gruff logger, possibly sporting a thin beard, chopping firewood outside of the cabin surrounded by a gaggle of spawn.
"I had to return my mail order bride Tawnya as she reached the point of maximum impact and the Russian Time-bomb detonated."