Snow and Ice
 
 
What do snowpacks and ice cores tell us about seasonal variation in weather?

Once snow falls to the ground, it begins a process of change. Pressure, temperature and moisture change the form of the snowflake's crystals and the texture. Additional snowfalls, rain or sleet, and daytime surface melting followed by nighttime freezing all contribute to the changes. Studies of the snowpack are essential to protect people from the death and devastation of avalanches and flooding from spring melts. The layers of snow also preserve evidence of weather change and can be analyzed the way a geologist analyzes layers of rock. Year to year comparisons can help to understand climate change. Information from ice cores helps scientists understand how Earth's climate has varied over time. In the Greenland Ice Sheet Project 2, or GISP2, scientists drilled an ice core from the summit of the Greenland ice sheet all the way down to bedrock. A total of 10,116 feet (3,053 meters) of ice was retrieved. The process took five years to complete! This ice core records the past 110,000 years of Earth's climate history and provides one of the most detailed records for the Northern Hemisphere.

Man sitting in snow and writing on a notepadFrom Students:
The layers in snowpacks and ice cores tell a story of weather change over time. Make measurements of the layers in snow pits and ice cores, and compare your data with professional data.
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A weather station covered in snowFrom Weather Stations:
Professional ground-based observations of snow packs are made to predict avalanches and spring snowmelt, and to gather information on weather change. Data from deep cores of snow and ice in glaciers tell scientists about climate change.
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EarthFrom Satellites:
NASA satellites monitor snowpacks and glaciers from space to predict water resources and sea level change.
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After students dig their snowpits and analyze the layers, they compare their layer analysis data to the weather events they recorded at their site since the lowest level of snow fell. Students offer an explanation of each layer in terms of the record of temperatures, humidity, wind and snow fall. The purpose of the snow pit investigations are better understood if students are introduced to the concept of change, or metamorphosis, within a snowpack.

Included in the Related Resources section below are links to videos called Snow Pit Protocol and Ice Core/Thin Section Protocol prepared by Dr. Peter Wasilewski of NASA Goddard Space Flight Center. The link to the University of Colorado, Boulder, Web site provides information about making and analyzing snowpits. Snowpit: Snow on the Ground, a History of Winter product, found on the blueiceonline.com Web site, includes background information, pictures of crystals and an explanation of snow metamorphosis. The Modified UNESCO Classification, or MUC, code table for vegetative cover can be downloaded using the link in the Related Resources section. Print the pages and laminate them for use in the field.

Related Resources
Download MUC Code Table (PDF)
Greenland Ice Sheet Project 2  →
Snow Pit Protocol Video  →
Ice Core Thin Sectioning Video  →
University of Colorado, Snow Pit Web site  →
 
 
Find this article at:
 
http://www.nasa.gov/audience/foreducators/son/winter/snow_ice/F_Snow_and_Ice.html