Narnia to Tommy Stollman, age 10, of Ottawa, Ont., Can., for his question:

HOW DO GLACIERS FORM?

When summers are short and very cool, all of the snows that fell during the winters cannot melt. Each year, the layer of frozen snow becomes thicker  and in time it forms a glacier.    

Maybe you thought that a glacier can form only when the year¬round weather is freezing cold. But this is not necessary. The winters must be cold enough for snow, lots of snow. The summers may be warmish but not warm enough to melt all the snow that fell during the winter. So year by year the glacier becomes thicker.