The Science of Ice Freeze-up & Break-up

Everyone who has lived in the northern U.S. has observed the phenomenon known as freeze-up and break-up on local rivers, streams, and lakes.

What causes a river or lake to freeze-up in the fall? What causes a river or lake to melt out (break-up) in the spring? Have the dates of freeze-up and break-up changed in your area over the past few decades? You could have your students ask a long-time resident of the area whether they have noticed a change in the dates for freeze-up and break-up.

Globally, scientists have documented significant changes in the dates that bodies of water freeze over in the winter and thaw out in the spring. For an example, refer to “Magnuson, J.J. and 13 others. 2000. Historical trends in lake and river ice cover in the Northern Hemisphere. Science, 289(5485), 1743–1746″. An abstract is available online at the Science magazine website.

What changes are already occurring or could occur in your area, due to later freeze-ups and earlier break-ups?

If you have a stream or lake near your school, you can engage your students in investigating the freeze-up and break-up of a local body of water. The GLOBE project has developed a protocol that enables students to study freeze-up and break-up locally, the Ice Seasonality Investigation (pdf).


Leave A Comment

The MSP project is funded by an ESEA, Title II Part B Mathematics and Science Partnership Grant through the Montana Office of Public Instruction. MSP was developed by the Clark Fork Watershed Education Program and faculty from Montana Tech of The University of Montana and Montana State University, with support from other Montana University System Faculty.