Glaciers and polar ice store more water than lakes and rivers, groundwater, and the atmosphere combined. Ten percent of our world is under ice today, equaling the percent being farmed. If the world's ice caps thawed completely, sea level would rise enough to inundate half of the world's cities. The Greenland and Antarctic ice caps are 2 miles thick. Alaska is four percent ice.
Glaciers form because snowfall in the high mountains exceeds snowmelt.
The snowflakes first change to granular snow round ice grains but the accumulating weight soon presses it into solid ice. Eventually, gravity sets the ice mass flowing downslope at up to 7 feet per day. The park includes some 12 tidewater glaciers that calve into the bay. The show can be spectacular. As water undermines some ice fronts great blocks of ice up to 200 feet high break loose and crash into the water.