[ProtectOurFreedom]

It took 100,000 years to freeze all that water into glaciers; then the warming that started 20,000 years ago melted all that ice in 12,000 years. Just look at the western Missoula Floods and the Bonneville Flood caused by breaking ice dams for evidence 14,000 years ago.

[justa-hairyape]

The glaciers could have been mostly built up in a short period. Once you get glaciated, the oceans are cooled and evaporation is much less. You can get copious amounts of rain, while entering the glacial, because the oceans have a higher base temperature. And that can support massive El Nino’s. But once cooled, glaciated world, ocean temps are so low that El Ninos may not be warm enough to produce significant evaporation.

Still have no clue what ends the glacial.