World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0004446652
Reproduction Date:

Title: Snowmelt  
Author: World Heritage Encyclopedia
Language: English
Subject: Surface runoff, Glaciers of Bhutan, Flood control, Glen Aulin High Sierra Camp, Hamun Lake
Publisher: World Heritage Encyclopedia


Vegetation gives off heat, resulting in this circular snowmelt pattern.

In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high fractions of the annual runoff in a watershed. Predicting snowmelt runoff from a drainage basin may be a part of designing water control projects. Rapid snowmelt can cause flooding. If the snowmelt is then frozen, very dangerous conditions and accidents can occur, introducing the need for salt to melt the ice.

Energy fluxes related to snowmelt

There are several energy fluxes involved in the melting of snow.[1] These fluxes can act in opposing directions, that is either delivering heat to or removing heat from the snowpack. Ground heat flux is the energy delivered to the snowpack from the soil below by conduction. Radiation inputs to the snowpack include net shortwave (solar) and longwave radiation. Net shortwave radiation is the difference in energy received from the sun and that reflected by the snowpack due to the snowpack albedo. Longwave radiation is received by the snowpack from many sources, including ozone, carbon dioxide, and water vapor present in all levels of the atmosphere. Longwave radiation is also emitted by the snowpack in the form near-Black-body radiation, where snow has an emissivity between 0.97 and 1.0.[2] Generally the net longwave radiation term is negative, meaning a net loss of energy from the snowpack. Latent heat flux is the energy removed from or delivered to the snowpack which accompanies the mass transfers of evaporation, sublimation, or condensation. Sensible heat flux is the heat flux due to convection between the air and snowpack.

Historical Cases

In northern Alaska, the melt-date has advanced by 8 days since the mid-1960s. Decreased snowfall in winter followed by warmer spring conditions seems to be the cause for the advance. [3] In Europe, the recent heat wave has especially been anomalous at higher altitudes. For the first time on record, some of the highest Alpine peaks in Europe are snow-free. Although it would seem that the two are related, the question of how much of this is due to climate change firmly remains a center of debate. [4]

Increased water runoff due to snowmelt was a cause of many famous floods. One well-known example is the Red River Flood of 1997, when the Red River of the North in the Red River Valley of the United States and Canada flooded. Flooding in the Red River Valley is augmented by the fact that the river flows north through Winnipeg, Manitoba and into Lake Winnipeg. As snow in Minnesota, North Dakota, and South Dakota begins to melt and flow into the Red River, the presence of downstream ice can act as a dam and force upstream water to rise. Colder temperatures downstream can also potentially lead to freezing of water as it flows north, thus augmenting the ice dam problem. Some areas in British Columbia are also prone to snowmelt flooding as well.

See also

Scholarly Conversation

The date of annual melt is of great interest as a potential indicator of climate change. In order to determine whether the earlier disappearance of spring snow cover in northern Alaska is related to global warming verses an appearance of a more natural, continual cycle of the climate, further study and monitoring is necessary. [5]

Large year to year variability complicates the picture and furthers the debate. Inter-annual variability of springtime snow pack comes largely from variability of winter month precipitation which is in turn related to the variability of key patterns of atmospheric circulation.

A study of the mountains in the western United States show a region wide decline in spring snow-pack since the mid-1900s, dominated by loss at low elevations where winter temperatures are near freezing. These losses are an indication of increased temperatures which lead to snow loss via some combination of increased regularity of rain versus snow and increased melting during winter months. These natural variations make it challenging to quantify trends with confidence, to deduce observed changes to predict future climate, or to clearly detect changes in snow-pack due to human impact on warming trends. [6]


  1. ^ Gray, D.M., Male, D. H. (1981). Handbook of Snow: Principles, Processes, Management, and Use. Pergamon Press.  
  2. ^  
  3. ^ Stone, Robert (2002). "Earlier Spring Snowmelt in Northern Alaska as an Indicator of Climate Change.". Journal of Geophysical Research 107 (4089). 
  4. ^ Burt, Christopher. "Weather Extremes". Unprecedented Snow Melt and Heat in the European Alps. Weather Underground. Retrieved 4 October 2012. 
  5. ^ Hoffman, David. "Earth System Research Laboratory". Climate Monitoring and Diagnostics Laboratory Summary Report No. 24. U.S. Department of Commerce. Retrieved 4 October 2012. 
  6. ^ Minder, Justin (2009). "The Sensitivity of Mountain Snowpack Accumulation to Climate Warming". Journal of Climate 23: 2634–650.  
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.