Chiefio has been looking at Dansgaard-Oeschger and Heinrich events during the last Ice Age – go to http://chiefio.wordpress.com/2012/12/15/d-o-ride-my-see-saw-mr-bond/ … and in his conclusions says they differ from each other in how the ocean currents shift – and both must happen during a cold ocean regime. They also differ on how cold it is near Greenland when they begin. Bond events happen during a warm ocean regime etc. This appears to mark a major differentiation in the two types of event. Whereas Heirich events number just seven the Dansgaard-Oeschger events have been much more frequent. In spite of all this we need to be wary as it is clear major interstadials also litter the last Ice Age (warmings rather than coolings) and some of these may have been of a long duration – unlike the above cooling events, or the even more tenuous Bond events.