Ice blasting
Encyclopedia
Ice blasting is the use of explosives to break up ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

 in rivers, greatly aiding navigation systems.
This is done during the spring when snow is melting and river ice is breaking up. There is always a chance that the ice flows could collide creating an ice jam and blocking the river. The river, filled with melt water, will quickly flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

 and often cause damage to nearby settlements. Thus in most northern areas governments quickly act to break up the ice jams before they can do much damage. This is most easily done with explosives. These explosives may be planted from the shore, or in some cases by helicopter. Explosives can also be remotely delivered by artillery or dropped by bombers. In the large rivers of the Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

 the Russian airforce is sometimes called in to bomb ice jams.

Some districts, where flooding is especially common, do preemptive ice blasting. The city of Ottawa
Ottawa
Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, for instance, blasts the Rideau River
Rideau River
thumb|Rapids on the Rideau River opposite [[Carleton University]].The Rideau River is a Southern Ontario river which flows north from Upper Rideau Lake and empties into the Ottawa River at Rideau Falls in Ottawa, Ontario. Its length is 146 km...

 each spring to break up the ice. In 1994, for instance, 10,000 sticks of dynamite were used to break up ice along 9 kilometres of the river.

Ice blasting has a number of disadvantages. It is expensive and dangerous requiring highly skilled explosives experts. When blasting is occurring the public must be warned to keep their distance. The blasting has negative environmental consequences. Fish and other river creatures are inevitably killed and the river bottom is scarred. Unexploded ordnance
Unexploded ordnance
Unexploded ordnance are explosive weapons that did not explode when they were employed and still pose a risk of detonation, potentially many decades after they were used or discarded.While "UXO" is widely and informally used, munitions and explosives of...

can also be a concern where remote delivery is used.
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