My understanding is that the Lake Agassiz surge resulted in the Younger Dryas, 12,900 – 11,500 before the present (or 9900-8500 BC). I think the glacial lake Ojibway formed later, and Lake Agassiz filled up a little bit again, and then both resurged around the 8200 years ago but this didn't lead to as drastic nor as long of a drop in temperatures as the Younger Dryas.
So, the last glaciation reached its peak 20,000 years ago, and the world got lots warmer (and even wetter in some places (like the Sahara and the Middle East) but then when Lake Agassiz (a huge lake, 4 times larger than all the Great Lakes, filled with melted glacier water) burst all that fresh water spilled into the North Atlantic 12,000 years ago--well things got real cold and dry again in a hurry.
See what you and Blam have taught me after all these years on the GGG ping list?!
The Younger Dryas ended circa 11K BP; the Lake Missoula flood which produced the Channeled Scablands may be of that earlier date (I found it hard to nail down on the web, one proposed date is 14K BP), but that water went to the Pacific. :')
That's good. However, I'm learning at the same time as you.
Timing of various climate change events after the Ice Age meltdown started aroung 18,000 ya.
There are a lot of interesting conjectures and information, as well as maps in various works by Graham Hancock. There is also a Graham Hancock Forum site, with interesting information.