When the Rideau River in Ottawa, Canada freezes for the winter, the Rideau Valley Conservation Authority and city officials clear up the river's ice jams using a rather jarring method — blowing up the ice with dynamite.

Granted, the ice is first fractured using saws and amphibious excavators to diminish property damage and harm to river life. Notes the BBC:

Today's methods now involve much more ice cutting and much less dynamite. Before 1992, up to 8,000kg (17,636lb) of explosives would be used in a season. Today, it is between 700 and 1,500kg (1,543 to 3,000lb). This benefits wildlife habitats and also reduces the seismic impact on nearby bridges and other structures.

It costs the city $460,000 a year to clear the river ice, with 18 staff involved. But it's money well spent, says Turner. Without this work, some 900 buildings and other structures would be at risk of flood damage - and the clean-up costs would be far higher.

The blasting began this weekend and will continue into March, when the river hits peak water levels. So if you happen to be in Ottawa next month, you can witness a river exploding on purpose (as opposed to a river catching fire by accident).

[BBC via Treehugger]