Q. Where does the "ice age" fit in with creation?
A. What I think happened to atmospheric conditions on the earth after the Great Flood would explain the cause of the ice age/s. This explanation doesn't exactly have anything to do with "creation" except that it was due to what God did on Day 2 of the creation week that the Great Flood produced the effects it did after the floodwaters receded.
The geological explanation of ice ages from an evolutionary, old earth perspective is that any given ice age occurred over a span of 10s to 100s of thousands of years. An ice age involves the slow encroachment of glaciers (frozen rivers) further and further south from the North pole (and vice versa from the South pole) as the earth goes through a period of global cooling, i.e. the polar ice caps, both north and south grow very large. Then a long period of global warming occurs, and the polar ice caps shrink back. Millions of years later the process occurs again.
However, if the earth never really experienced extremes in the weather before the flood, due to the greenhouse effect caused by the water vapor canopy created by God on Day 2 of creation, there would have been no polar ice caps before the flood. There is, in fact, a lot of evidence that there were no polar ice caps on earth at one time. After the flood, the greenhouse effect caused by the canopy was lost, because the canopy was lost. The result was that huge amounts of snow began to fall on the poles where for the first time extremely cold temperatures now occurred. The snow and ice accumulated and pushed far down and up from the two poles--a great ice age. The explanation that there were many ice ages covering vast periods of time by evolutionists is simply a product of their bias towards reading extreme age into every geological formation they observe. An alternate explanation is that with such catastrophic changes in atmospheric weather patterns, the formation of polar ice caps and extreme differences in temperatures in various parts of the earth, the weather patterns on earth were in great flux. A large amount of melting and refreezing would have been taking place--perhaps for 100s of years--causing rapid movement of the ice fronts towards and away from the warmer regions extending away from the equator. Finally, the overall weather patterns reached a fairly stable equilibrium--the result being the fairly stable polar ice caps we have today.
If you are interested in reading more about this subject, I recommend, THE GENESIS FLOOD by Whitcomb and Morris. Look in the index under "Glacial period" and "Glaciation, continental."