What images come to mind when you think of the Ice Age? Woolly mammoths lumbering across the frozen ground? An endless, snow-white landscape?

Those things and more probably come to mind. For many, the image most often associated with the Ice Age is of huge mountains ice slowly inching across the ground, flattening everything in their path. What are we talking about? Glaciers, that is!

The Ice Age is long gone. In fact, scientists these days are increasingly warning residents of Earth about the dangers of global warming. In our modern world, do glaciers still exist?

You bet they do! In fact, glaciers can be found on every continent except Australia. Most of the world's glaciers are located near the North and South Poles, especially Antarctica and Greenland.

Glaciers can be located anywhere the right conditions exist. Areas with high snowfall in winter followed by cool temperatures in summer are prime locations for glaciers. This is why most glaciers are located above the snow line in areas that receive a lot of snow each winter, such as mountainous or polar areas.

Glaciers form when large amounts of snow accumulate over time. In areas where more snow falls in winter than evaporates or melts in summer, the accumulated snow that survives forms a dense, compressed layer called firn.

As additional layers are added in subsequent years, the layers of firn slowly form thick layers of ice that begin to flow outward and downward under the pressure of their own weight. When this happens, a glacier is born!

There are two types of glaciers. Valley glaciers, also known as alpine glaciers, form in mountainous areas where their movement is constrained by valley walls. Continental glaciers, also known as ice sheets, are dome-shaped masses of ice that flow outward in all directions.

Glacier growth depends upon heavy snowfall each winter. Many people assume that extremely cold areas will have lots of glaciers. That's not necessarily the case, though. For example, the Siberia area of Russia is known for its brutally cold winters. With a dry climate, though, Siberia doesn't receive enough snowfall and thus has almost no glaciers.

Unfortunately, scientists who monitor glaciers have noticed that the world's glaciers have been decreasing in length and volume over the course of the last century. This worldwide retreat of glaciers has been linked to climate change. For example, Glacier National Park had around 150 glaciers when the park opened in 1910. Today, there are fewer than 30 left, and some experts believe the remaining glaciers will disappear within the next 15 years.

Wonder What's Next?

Join us in Wonderopolis tomorrow as we greet a new season!