Even in the coldest climates it takes years to freeze. Glaciers are not found everywhere for the simple reason that it isn't cold enough. Even in places where it is quite cold in the winter, in the summer everything that is frozen will melt. Glaciers are mostly found in Iceland, the Arctic, Antarctica, Alaska, and Canada. During the ice age a lot of glaciers were formed.
Scientists say there have been three ice ages in the past.
The first was about 600 million years ago. The next 200 million years ago and the most recent 8 million years ago. This one ended about 7,000 years before today. When a a glacier is totally frozen, it can last for a long time. Up to five thousand years.