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Austin Post

Publications and source records attributed to Austin Post.

At least 19 recordsLinked to original sources
USGS2006

Inventory of glaciers in the Sierra Nevada, California

All perennial bodies of ice in the Sierra Nevada are listed and classified. The inventory includes 497 glaciers covering a total area of 50 square kilometers and 788 small ice bodies which do not meet the definition of a glacier, covering a total of 13 square kilometers. The listings include each ice body's drainage basin, location, orientation, altitude, area, and length the glaciers are also classified as to form, source, surface condition, and nature and activity of the terminus.

California↗
USGS2000

Preliminary bathymetry of Shoup Basin and late Holocene changes of Shoup Glacier, Alaska

Shoup Glacier is a retreating, tidewater-calving glacier in northeast Prince William Sound, Alaska. Historical records, vegetation distribution, and sediment depth in Shoup Bay indicate that the glacier reached a late Holocene maximum at the mouth of Shoup Bay prior to 1750. When first observed around 1900, the terminus was stable on a series of shallow, bedrock obstructions between Shoup Bay and Shoup Basin, 2 miles from the late Holocene maximum. Shoup Glacier receded into tidewater in 1957 and in the following 33 years retreated 1.3 miles to expose Shoup Basin, a deep (more than 350 feet) basin with virtually no sediment accumulation. Shoup Glacier is expected to stabilize at the head of Shoup Basin shortly after the year 2000 and will not readvance if present climatic conditions continue.

Alaska↗
USGS1995

Glaciers: A water resource

Most Americans have never seen a glacier, and most would say that glaciers are rare features found only in inaccessible, isolated wilderness mountains. Are they really so rare? Or are they really potentially important sources of water supply?

General Information Product↗
USGS1981

Effects of volcanism on the glaciers of Mount St. Helens

The cataclysmic eruption of Mount St. Helens May 18, 1980, removed 2.9 km 2 (about 0.13 km 3 ) of glacier snow and ice including a large part of Shoestring, Forsyth, Wishbone, Ape, Nelson, and all of Loowit and Leschi Glaciers. Minor eruptions and bulging of the volcano from March 27 to May 17 shattered glaciers which were on the deforming rock and deposited ash on other glaciers. Thick ash layers persisted after the May 18 eruption through the summer on most of the remaining snow and ice, and protected winter snow from melting on Swift and Dryer Glaciers. Melting and recrystalization of snow and ice surviving on Mount St. Helens could cause and lubricate mudflows and generate outburst floods. Study of glaciers that remain on this active volcano may assist in recognizing potential hazards on other volcanoes and lead to new contributions to knowledge of the transient response of glaciers to changes in mass balance or geometry.

Washington↗
USGS1980

Columbia Glacier, Alaska: Recent ice loss and its relationship to seasonal terminal embayments, thinning, and glacial flow

In 1974 the U.S. Geological Survey began an intensive investigation of the stability of Columbia Glacier, a calving tidewater glacier terminating in Columbia Bay, near Valdez, Alaska. Aerial photographs taken in 1957 and a sequence of photographs taken at about 2-month intervals since 1976, when analyzed photogrammetrically, provided detailed data on changes in Columbia Glacier's thickness, flow rate, and terminal position. Annual embayments in the glacier 's terminus form during the summer-autumn season in most years; the size of embayments appears to be related to (1) the thickness of the glacier, and (2) the position and nature of subglacial freshwater discharge. Embayments have apparently increased in size in recent years; the largest embayments yet observed formed in 1975, 1976, 1977, and 1978. From April 1, 1977, to April 1, 1978, the total volume of ice calved was about 1.0 cubic kilometer. By January 1979 the glacier front had retreated from Heather Island. Glacier flow varies seasonally and synchronously in the lower 17 kilometers of the glacier; large accelerations occur near the terminus in response to embayment formation. Daily speed within 5 kilometers of the terminus increased from about 1.9 meters per day between 1963 and 1968 to about 2.7 meters per day between 1977 and 1978. In the lowest 15 kilometers, the glacier surface was lowered about 9 meters between 1957 and 1974, and about 13 meters between 1974 and 1978. Columbia Glacier is being reduced in mass due, in part, to recent losses caused by large embayments forming annually. If such reduction continues it will result in a drastic retreat.

Alaska↗
USGS1980

Preliminary bathymetry of Northwestern Fiord and neoglacial changes of Northwestern Glacier, Alaska

The first preliminary bathymetry (at 1:20,000 scale) and other scientific investigations of Northwestern Fiord, Alaska, were conducted by the Research Vessel Growler in 1978, disclosing this 10.5-mile-long branched waterway to be a deep basin enclosed by a terminal-moraine shoal. The basin was formerly filled by Northwestern Glacier, which began a drastic retreat around 1909 and reached the head of the main arm around 1960. Soundings and profiles show the main channel to be as much as 970 feet deep and to have the typical U shape of a severely glacially eroded valley; since the glacier 's retreat, sediments have formed nearly level deposits in the deepest reaches, while the rest of the basin has a hard, rocky bottom. Preneoglacial forest debris dated by carbon-14 indicates Northwestern Glacier to have advanced into the fiord prior to 1,385 years before present (B.P.); a branch glacier evidently advanced into forest 1,635 years B.P. The combined glaciers from several arms culminated on the present terminal-moraine shoal around 1894. (USGS)

Alaska↗
USGS1975

Recurrent geothermally induced debris avalanches on Boulder Glacier, Mount Baker, Washington

Avalanches of snow, firn and hydrothermally altered rock and mud have been released six times since 1958 from Sherman Peak, part of the crater rim south of the main summit of Mount Baker, Wash. The avalanches traveled nearly identical paths 2.0-2.6 km down Boulder Glacier on the east slope of the volcano. Debris from at least one past avalanche can be seen as a thin bed of acidic mud in the glacier terminus. Fumaroles. thermal springs, and areas of warm ground, some of which are subglacial, are concentrated in the crater and were mapped by aerial infrared thermography. The outgoing radiant flux per unit area from a cluster of infrared anomalies within 50-150 m of the avalanche source was estimated to be 319 W m -2 (7,620 μ cal cm -2 s -1 ) in November 1972, which is sufficient to account for observed ice perforations. In addition vapor emission, not apparent in thermography, was observed along the source margin after the avalanche of August 1973. The principal conditions that produce the avalanches are considered to be the large accumulation of snow and firn on top of hydrothermally altered clay-rich ground at Sherman Peak and the saturation near the ground-firn interface by melt water produced both by summer snow ablation and by geothermal emission. The periodic avalanches have a potential for impounding water in the crater in addition to ponded water already known to occur. Sudden release of impounded water could present a danger to the Boulder Creek valley below.

Washington↗