Ice jam

Ice jams usually occur in spring, but they can happen as winter sets in when the downstream part becomes frozen first.

Freeze-up jams may be larger because the ice is stronger and temperatures are continuing to cool unlike a spring break-up when the environment is warming, but are less likely to suddenly release water.

The jam induces flow restriction, either or both because of increased friction along the ice under surface and because of a decrease in the channel's cross-sectional area.

[11] A jave is a wave generated in a river as an ice jam breaks up and releases the water that accumulated behind it.

These events may induce a rise in water level in the range of decimeters per minute, with celerities of 2–10 meters per second and an increase in discharge by a factor of 2.75.

Vulnerability involves exposure and susceptibility of different types of residential and commercial buildings within the floodplain area or in between specification periods of floods.

The process involves using software tools (possibly GIS) to add data layers, calculate flood depths, and extrapolate water levels for the transects to the downtown area.

[7] The prevention of ice jams may be accomplished by Where floods threaten human habitation, the blockage may be artificially cleared.

Occasionally, military aircraft have been used to bomb ice jams with limited success as part of an effort to clear them.