On Rivers
If the upstream part of a river thaws first (possibly because it flows away from the equator), and the ice gets carried downstream into the still-frozen part, the ice can form an ice dam and flood the areas upstream of the jam. This occurred during the 2009 Red River Flood and the 2009 Alaska floods. After the ice dam breaks apart, the sudden surge of water that breaks through the dam can then flood areas downstream of the jam. While this usually occurs in spring, it can happen as winter sets in when the downstream part becomes frozen first. Where floods threaten human habitation, the blockage may be artificially cleared. Ice blasting using dynamite may be used, as well as other mechanical means.
Read more about this topic: Ice Dam
Famous quotes containing the word rivers:
“The whole tree itself is but one leaf, and rivers are still vaster leaves whose pulp is intervening earth, and towns and cities are the ova of insects in their axils.”
—Henry David Thoreau (1817–1862)
“The whole appearance is a toy. For this,
The dove in the belly builds his nest and coos,
Selah, tempestuous bird. How is it that
The rivers shine and hold their mirrors up,
Like excellence collecting excellence?”
—Wallace Stevens (1879–1955)