Rain warning lifts as Calgary braces for river crest

Calgary's rainfall warning is lifting as the heaviest downpour moves out, but the city's rivers are still rising — and that's where the real watch begins.

Environment Canada says Calgary will see just 5 to 10 millimetres more rain Tuesday after 40 to 70 millimetres fell over the weekend. The forecast clears by Wednesday. But the Bow River is expected to crest at around 480 cubic metres per second — double the advisory threshold — while the Elbow will hit 100 cubic metres per second, triple its threshold.

Those numbers look alarming until you compare them to 2013. Calgary's rivers hit over 2,000 cubic metres per second during that historic flood. The difference now is infrastructure: $1.3 billion in new reservoirs, community flood barriers, pumping stations and improved forecasting have eliminated more than 70 per cent of the damage potential from a similar event.

The city has lowered the Glenmore Reservoir to make room for rising Elbow flow, and TransAlta's Ghost Reservoir is managing upstream release. Calgary Fire Department is keeping high stream flow advisories in place and asking people to stay off riverbanks — cold water and hidden hazards make it dangerous.

Pathway closures are in effect at several downtown underpasses and along both river corridors. The boating advisory remains. Residents are asked to watch storm drains and report pooling water that doesn't drain within 90 minutes via the 311 app.

The city is in a much stronger position than thirteen years ago. What was once an existential flood threat is now a managed high-water event.