It was a storm the city of North Bay, Ontario remembers well.
A combination of heavy rain and a beaver dam breaking caused significant damage to homes and roads during a downpour in late April, 2011.
"We had a rain storm that probably wouldn't have caused any problems, other than the fact that a big beaver dam broke, and that made 4-5 times more water come down quickly. It overwhelmed our storm systems," says Alan Korell, Director of North Bay Public Works.
City crews are now using cages on the outside of culverts in the area to discourage beavers from building dams.
These days, animals are a small problem when it comes to storm-sewer management.
Korell says that big storms are happening more often these days, and that's made them change the way they look at - and manage - things.
Now, cities like North Bay are spending more time, money and effort on making sure storm sewers are ready for almost anything.