Most people think of the Ice Age as something that happened so long ago that not a sign of it remains. But did you know that geologists say we are just now reaching the end of the Ice Age? And people who live in Greenland are actually still in the Ice Age as far as they're concerned.
About 25,000 years ago, any people who may have been living in central North America saw ice and snow the year around. There was a great wall of ice that stretched from coast to coast, and the ice extended northward without an end. This was the latest Ice Age, and all of Canada, much of the United States and most of northwestern Europe were covered by a sheet of ice over 1000 metres thick.
This didn't mean taht it is was always icy cold. The temperature was only about 5 degrees lower than it is now in Northern United States. What caused the Ice Age was that the summers were very cool. SO there wasn't enough heat during the summer months to melt away the winter's ice and snow. It just continued to pile up until it covered all the northern area.
But the Ice Age consisted of really four periods. During each period the ice formed and advanced, then melted back towards the North Pole. It is believed this happened four times. The cold periods are called "glaciations", and the warm periods are called "interglacial" periods.
It is believed that in North America the first period of ice came about 2,000,000 years ago, the second about 1,250,000 years ago, the third about 500,000 years ago, and the ,last about 100,000 years ago.
The last Ice Age didn't melt at the same rate everywhere. For example, cie that reached what is now Wisconsin began to melt about 40,000 years ago. But ice that had covered New England melted about 28,000 years ago. And there was ice covering what is now Minnesota until about 15,000 years ago!In Europe, Germany got from under the ice 17,000 years ago and Sweden remanined covered with ice until about 13,000 years ago!