Whitney Glacier
Encyclopedia
The Whitney Glacier is a glacier
situated on Mount Shasta
, in the U.S. state
of California
. The Whitney Glacier is the longest glacier and the only valley glacier in California. In area and volume, it ranks second in the state behind the nearby Hotlum Glacier
. In 1986, the glacier was measured to be 126 feet (38 m) deep and over three km in length. The glacier starts on Mount Shasta's Misery Hill at 13,700 feet (4,200 m
) and then it flows northwestward down to the saddle between Mount Shasta and Shastina. There is a major icefall
that occurs there since the ground is very uneven at 11,800 feet (3,600 m). Past the icefall, the glacier flows down the valley between Mount Shasta and Shastina with the terminus
at 9,500 to 9,800 feet (2,900–3,000 m).
s nearly doubling, the Bolam Glacier
increasing by half, and the Whitney and Konwakiton Glaciers growing by a third. The study concluded that though there has been a two to three degree Celsius
temperature rise in the region, there has also been a corresponding increase in the amount of snowfall. Increased temperatures have tapped Pacific Ocean
moisture, leading to snowfalls that supply the accumulation zone
of the glacier with 40 percent more snowfall than is melted in the ablation zone
. Over the past 50 years, the glacier has actually expanded 30 percent, which is the opposite of what is being observed in most areas of the world. Researchers have also stated that if the global warming
forecast for the upcoming next 100 years are accurate, the increased snowfall will not be enough to offset the increased melting, and the glacier is then likely to retreat.
Note that both these references make the claim that the Whitney Glacier is now the only glacier in the world known to be larger than it was in 1890, but this is erroneous. For example, several glaciers in Alaska, most notably the Hubbard Glacier
, are larger now than in 1890. However, Hubbard Glacier, along with a few other notable glaciers whose termini are at sea level, is what is known as a calving
glacier. "Glaciologists often point out that glaciers are sensitive indicators of climate. This paradigm should not be applied to calving glaciers. During most of the calving glacier cycle, the slow advances and relatively rapid retreats are not very sensitive to climate. For example, the calving glaciers that are currently growing and advancing in the face of global warming, were retreating throughout the little ice age. Calving glaciers become sensitive to climate only late in the advancing phase, when the mass flux out of the accumulation area approaches the mass lost by melting in the ablation area and losses due to calving can no longer be replaced. No reasonable change in climate will change this imbalance and stop the advances of these few glaciers".
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
situated on Mount Shasta
Mount Shasta
Mount Shasta is located at the southern end of the Cascade Range in Siskiyou County, California and at is the second highest peak in the Cascades and the fifth highest in California...
, in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The Whitney Glacier is the longest glacier and the only valley glacier in California. In area and volume, it ranks second in the state behind the nearby Hotlum Glacier
Hotlum Glacier
The Hotlum Glacier is a glacier situated on the northeast flank of Mount Shasta, in the U.S. state of California. It is the largest and most voluminous glacier in California, although not as thick or long as the nearby Whitney Glacier...
. In 1986, the glacier was measured to be 126 feet (38 m) deep and over three km in length. The glacier starts on Mount Shasta's Misery Hill at 13,700 feet (4,200 m
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
) and then it flows northwestward down to the saddle between Mount Shasta and Shastina. There is a major icefall
Icefall
An icefall is a portion of some glaciers characterized by rapid flow and a chaotic crevassed surface. Perhaps the most conspicuous consequence of glacier flow, icefalls occur where the glacier bed steepens and/or narrows...
that occurs there since the ground is very uneven at 11,800 feet (3,600 m). Past the icefall, the glacier flows down the valley between Mount Shasta and Shastina with the terminus
Glacier terminus
A glacier terminus, or snout, is the end of a glacier at any given point in time. Although glaciers seem motionless to the observer, in reality glaciers are in endless motion and the glacier terminus is always either advancing or retreating...
at 9,500 to 9,800 feet (2,900–3,000 m).
Advance of Whitney Glacier
In 2002, scientists made the first detailed survey of Mount Shasta's glaciers in 50 years. They found that seven of the glaciers have grown over the period 1951-2002, with the Hotlum and Wintun GlacierWintun Glacier
The Wintun Glacier is a glacier situated on the eastern flank of Mount Shasta, in the U.S. state of California. It is both the third largest and third most voluminous glacier in California after the neighboring Hotlum Glacier and the Whitney Glacier...
s nearly doubling, the Bolam Glacier
Bolam Glacier
The Bolam Glacier is a glacier situated on the northern flank of Mount Shasta, in the U.S. state of California. It is the second longest glacier in California behind the nearby Whitney Glacier, and the fourth largest and most voluminous after the neighboring Hotlum Glacier, Whitney Glacier, and...
increasing by half, and the Whitney and Konwakiton Glaciers growing by a third. The study concluded that though there has been a two to three degree Celsius
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
temperature rise in the region, there has also been a corresponding increase in the amount of snowfall. Increased temperatures have tapped Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
moisture, leading to snowfalls that supply the accumulation zone
Accumulation zone
On a glacier, the accumulation zone is the area above the firn line, where snowfall accumulates and exceeds the losses from ablation, . The annual Glacier equilibrium line separates the accumulation and ablation zone annually...
of the glacier with 40 percent more snowfall than is melted in the ablation zone
Ablation zone
Ablation zone refers to the low altitude area of a glacier or ice sheet where there is a net loss in ice mass due to melting, sublimation, evaporation, or calving. The ablation zone is delineated by the equilibrium line altitude , or snow line, which separates the ablation zone and the high...
. Over the past 50 years, the glacier has actually expanded 30 percent, which is the opposite of what is being observed in most areas of the world. Researchers have also stated that if the global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
forecast for the upcoming next 100 years are accurate, the increased snowfall will not be enough to offset the increased melting, and the glacier is then likely to retreat.
Note that both these references make the claim that the Whitney Glacier is now the only glacier in the world known to be larger than it was in 1890, but this is erroneous. For example, several glaciers in Alaska, most notably the Hubbard Glacier
Hubbard Glacier
Hubbard Glacier is a glacier located in eastern Alaska and part of Canada.The longest source for Hubbard Glacier originates from its snout and is located at about at about , approximately west of Mt. Walsh with an altitude around . A shorter tributary glacier begins at the easternmost summit on...
, are larger now than in 1890. However, Hubbard Glacier, along with a few other notable glaciers whose termini are at sea level, is what is known as a calving
Ice calving
Ice calving, also known as glacier calving or iceberg calving, is a form of ice ablation or ice disruption. It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse...
glacier. "Glaciologists often point out that glaciers are sensitive indicators of climate. This paradigm should not be applied to calving glaciers. During most of the calving glacier cycle, the slow advances and relatively rapid retreats are not very sensitive to climate. For example, the calving glaciers that are currently growing and advancing in the face of global warming, were retreating throughout the little ice age. Calving glaciers become sensitive to climate only late in the advancing phase, when the mass flux out of the accumulation area approaches the mass lost by melting in the ablation area and losses due to calving can no longer be replaced. No reasonable change in climate will change this imbalance and stop the advances of these few glaciers".