Unprecedented outbreaks of native bark beetles are occurring in forests throughout the mountains of western North America. Any one of these events would be unusual; their simultaneous occurrence is nothing short of remarkable. Significant biogeographical events are occurring at a continental scale, and a warming climate is the one commonality across all of these spectacular outbreak events. Mountain pine beetle (Dendroctonus ponderosae Hopkins) populations are responsible for three of the more impressive of these events, and we describe recent case histories that illustrate the unique attributes of the current situation. These case histories involve outbreaks within the current range of mountain pine beetle in areas with micro-climate that were previously too cold; unusually large and intense outbreaks in high elevation pines; and range expansion north and east beyond the historical distribution in Canada. In this article we describe each of these three situations and briefly discuss their importance with respect to global climate warming.