Under Devils Thumb - The Cryosphere in Southeast

Here in rainy Southeast Alaska we probably take our water for granted. With over 100 inches of precipitation per year, micro climatic changes do not seem readily apparent. The snow capped mountains of the Coast Range are a visual indicator of the geological/hydrological processes of the cryosphere, a visual laboratory observed right from our classroom window. Water and ice are the reason this community is located where it is: abundant stream filled with salmon and glacial ice used for early cold storage facilities. It is not an uncommon sight for icebergs to follow the tides and wind right into the Wrangell Narrow and end up high and dry on the beach in front of your home.

This weeks module, filled with more information than any digital immigrant can possibly digest, hinted that climate events can occur quickly, sometimes as rapidly as 1 to 3 years. The TD video Climate Change suggested that if a particular critical threshold is crossed, the result can trigger sudden changes in the climate. These "triggers" are undefined except for the example of dramatic changes in greenhouse gasses.

Using the Alaska Climate Summaries site I was able to compare the period 1949 - 1983 to 1983- 205. Historical data show a 1.9º increase in the average high temp, a 1.2º increase in the average low temp and a nearly 45 inch decrease in average winter snowfall. Overall this seems rather substantial, especially when combined with data from further north. My students (5th grade) are currently working on a project to write a synopsis of climate data for Petersburg to be added to the Petersburg Wikipedia page. We were going to use Weather Underground but now I am planning on adding this information into the mix. This project not only helps us define what a wiki is and it's value, but it will allow us to take a peak at this data in the context of a real project and possibly look for correlations with other geo and climatic phenomena.

The dramatic changes in glaciers is the theme of the Extreme Ice Survey. James Balog and his team have mounted time lapse cameras to capture real time movement of glaciers across the planet. Added as a layer to Google Earth, it becomes a powerful teaching tool in any classroom. Here in Petersburg, our high school has implemented their own version of the Extreme Ice Survey.

Beginning in 1983, lead by geology teacher, Paul Bowen, groups of Petersburg high school seniors have been surveying the face of the Le Conte Glacier, located approx 15 miles south of town. The project web site, linked through the district web page includes maps, photos and videos, including a short synopsis by the current instructor, Vic Troutman. This is a powerful learning experience for all who participate and is another instance of students doing real science.