FAQ's about Glaciers

Although Mount Rainier (Washington) has not produced a significant eruption in the past 500 years, it is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Mount Rainier has 26 glaciers containing more than five times as much snow and ice as all the other Cascade volcanoes combined. If only a small part of this ice were melted by volcanic activity, it would yield enough water to trigger enormous lahars. Mount Rainier's potential for generating destructive mudflows is enhanced by its great height above surrounding valleys. -- From: Scott, et.al., 1990, Sedimentology, Behavior, and Hazards of Debris Flows at Mount Rainier, Washington: USGS Open-File Report 90-385, and Brantley, 1994, Volcanoes of the United States: USGS General Interest Publication.

There is no certain answer. There are 616 officially named glaciers in Alaska (see USGS Geographic Names Information System online data base), and many more unnamed glaciers. The Alaska Almanac estimates that Alaska has 100,000 glaciers -- that's a pretty good estimate.

Because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears.

No one knows for sure what would happen if the snow and ice in the polar regions all melted. Sea level would rise, which would flood coastal regions. Climate would be affected worldwide. Isostatic rebound would occur where ice masses were removed from continents, causing the land surface there to rise. Many scientists are trying to predict the effects of climate changes such as a general warming trend by using computer climate models. Much more research needs to be done before we can confidently predict results.

No - indeed, all of the physical, thermal and electrical properties of "regular icebox ice" and glacier ice are identical: density, viscosity, heat of fusion, latent heat, heat capacity, dielectric constant, thermal conductivity, absorption, emissivity, etc. The few small differences in characteristics are solely due to grain size differences. NOTE: High pressure forms of ice with different properties have been produced in laboratory experiments, but none occur naturally on earth, not even at the base of the Antarctic or Greenland ice sheets.

Mount Garibaldi (British Columbia, Canada) is a composite cone and domes built on a glacier. It is one of the larger volcanoes (6.5 cubic kilometers) in a chain of small Quaternary volcanic piles -- the Garibaldi Belt -- within the southern Coast Mountains of British Columbia. Mount Garibaldi is noteworthy both for the excellent exposures of its internal structure and for its striking topographic anomalies, which can be attributed to the growth of the volcano onto a major glacial stream, part of the Cordilleran Ice Sheet, and the subsequent collapse of the flanks of the volcano with the melting of the ice. -- From: Wood and Kienle, 1990, Volcanoes of North America: United States and Canada: Cambridge University Press, 354p., p.144-145, Contribution by William H. Mathews

Mount Rainier (Washington) at 14,410 feet (4,393 meters), the highest peak in the Cascade Range, is a dormant volcano whose load of glacier ice exceeds that of any other mountain in the conterminous United States. Mount Rainier has 26 glaciers containing more than five times as much snow and ice as all the other Cascade volcanoes combined. Mount Baker (Washington) at 10,778 feet (3,285 meters), is an ice-clad volcano in the North Cascades of Washington State about 31 miles due east of the city of Bellingham. After Mount Rainier, it is the most heavily glaciated of the Cascade volcanoes: the volume of snow and ice on Mount Baker (about 1.8 cubic kilometers; 0.43 cubic mile) is greater than that of all the other Cascades volcanoes (except Rainier) combined. -- From: Hoblitt, et.al., 1995, Volcano hazards from Mount Rainier, Washington: USGS Open-File Report 95-273, Brantley, 1994, Volcanoes of the United States: USGS General Interest Publication, and Gardner, et.al., 1995, Potential Volcanic Hazards from Future Activity of Mount Baker, Washington: USGS Open-File Report 95-498.

No one knows for sure. In the Devils Hole, Nevada paleoclimate record, the last four interglaciations lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 -years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stand, and would suggest that an equally long duration should be inferred for the current interglacial period as well. Work in progress on Devils Hole data for the period 60,000 to 5,000 years ago indicates that current interglacial temperature conditions may have already persisted for 17,000 years. Other workers have suggested that the current interglaciation might last tens of thousands of years.

See:

Winograd, I.J., Landwehr, J.M., Ludwig, K.R., Coplen, T.B., and Riggs, A.C, 1997, Duration and structure of the past four interglaciations: Quaternary Research, v. 48, p. 141-154.

Muhs, D.R., Simmons, K.R., and Steinke, B., 2002, Timing and warmth of the last interglacial period: New U-series evidence from Hawaii and Bermuda and a new fossil compilation for North America: Quaternary Science Reviews, v. 21, p. 1355-1383.

Paillard, D., 2001, Glacial cycles: Toward a new paradigm: Reviews of Geophysics, v. 39, p. 325-346.

Explore the variety of USGS resources on polar research, from maps and fact sheets to photographs and databases. Especially note Fact Sheet 2007-3013, "International Polar Year: Science at the Ends of the Earth".