Presently, 10 percent of land area on Earth is covered with glacial ice, including glaciers, ice caps, and the ice sheets of Greenland and Antarctica. Glacierized areas cover over 15 million square kilometers (5.8 million square miles).

Glaciers store about 69 percent of the world’s fresh water.

During the maximum point of the last ice age, glaciers covered about 32 percent of the total land area.

Starting around the early 14th century, and lasting to the mid-19th century, the world experienced a “Little Ice Age,” when temperatures were consistently cool enough for glaciers to advance in many areas of the world.

In the United States

In the United States, glaciers cover over 90,000 square kilometers (35,000 square miles). Most of those glaciers are located in Alaska, which holds 87,000 square kilometers (34,000 square miles) of glacial ice.

If all land ice melted, sea level would rise approximately 70 meters (230 feet) worldwide.

Glacier ice

Glacier ice crystals can grow to be as large as baseballs.

Glacial ice often appears blue when it has become very dense and free of bubbles. Years of compression gradually make the ice denser over time, forcing out the tiny air pockets between crystals. When glacier ice becomes extremely dense, the ice absorbs a small amount of red light, leaving a bluish tint in the reflected light, which is what we see. When glacier ice is white, that usually means that there are many tiny air bubbles still in the ice.

North America’s longest glacier is the Bering Glacier in Alaska, measuring 190 kilometers (118 miles) long.

The Kutiah Glacier

The Kutiah Glacier in Pakistan holds the record for the fastest glacial surge. In 1953, it raced more than 12 kilometers (7.5 miles) in three months, averaging about 112 meters (367 feet) per day.

In Washington State, the state with the largest area of glaciers in the contiguous United States, melting glaciers provide 1.8 trillion liters (470 billion gallons) of water each summer.

The largest glacier in the world is the Lambert-Fisher Glacier in Antarctica. At 400 kilometers (250 miles) long, and up to 100 kilometers (60 miles) wide, this ice stream alone drains about 8 percent of the Antarctic Ice Sheet.

Glacier

A glacier (US: /ˈɡleɪʃər/ or UK: /ˈɡlæsiər, ˈɡleɪsiər/) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. Glaciers slowly deform and flow under stresses induced by their weight, creating crevasses, seracs, and other distinguishing features. They also abrade rock and debris from their substrate to create landforms such as cirques, moraines, or fjords. Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that forms on the surface of bodies of water.

Etymology and related terms

The word glacier is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, and ultimately Latin glaciēs, meaning “ice”.^[8] The processes and features caused by or related to glaciers are referred to as glacial. The process of glacier establishment, growth and flow is called glaciation. The corresponding area of study is called glaciology. Glaciers are important components of the global cryosphere.

Classification by size, shape and behavior

Glaciers are categorized by their morphology, thermal characteristics, and behavior. Alpine glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier.^[9] A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field.^[10] Ice caps have an area less than 50,000 km² (19,000 sq mi) by definition.

resource: wikipedia