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Understanding river flow rates

What river flow rates mean

Check Alberta's River Monitoring Centre for river flow information

The Government of Alberta provides river forecasts, and the City of Calgary models forecasts and flows using this information to monitor and respond to high river flows.

River flow triggers and their impacts

Want to learn more about what triggers impact river flow for the Elbow River and Bow River? View the Elbow River Triggers and Bow River Triggers or review the tables below.

Bow River Triggers - Upstream of where the Bow River meets the Elbow River

Flow rate (m3/s) ​Chance of occurring in any given year ​Effect
250 m3/s
70 - 400
Normal seasonal river flow
(approximately May 15 to July)
​> 50% ​Riverside pathways impacted
550 m3/s
401-708
Higher than normal seasonal river flow
50% ​Heritage Drive/Glenmore Trail underpass inundated with water
927 m3/s
700
Flow in excess of channel capacity
​12% Overbank flooding may reach some homes
Evacuation may begin (potentially Bowness, Sunnyside and Hillhurst)
Temporary barrier construction is triggered
Prince's Island inundated with water

Elbow River Triggers - Downstream of Glenmore Reservoir

Flow rate (m3/s) ​Chance of occurring in any given year ​Effect
40 m3/s
< 30 - 90
Normal seasonal river flow
(approximately May 15 to July)
> 50% ​Riverside pathways impacted
120 m3/s
90 - 170
Higher than normal seasonal river flow
29% ​Modest overbank flooding occurs in mostly unpopulated areas
275 m3/s
170
Flow in excess of channel capacity
​5% Widespread evacuation
Significant construction of temporary barriers

To see river flow data from previous years, please go to historical river flow data in The City of Calgary.

Understanding provincial warnings

If necessary, the Government of Alberta may issue a warning or advisory based on the current river flow data. To see the latest warnings, notices and advisories: visit current river advisories and warnings.

Types of emergency alerts

Weather advisory
An advisory is a type of alert issued by Environment Canada when a certain weather or environmental hazard is either occurring, imminent or expected to occur. Pay attention for further information on the potential weather event.

Weather watch
A watch is issued when conditions are favourable for the development of a weather or environmental hazard that may post a significant threat to public safety and property. Continue to monitor weather conditions and take appropriate precautions.

Weather warning
A warning is an urgent message issued when a hazardous weather or environmental event that poses a significant threat to public safety and property is certain or imminent. Seek appropriate shelter and continue to monitor conditions. For more information, visit Weather Canada.

High stream-flow advisory
This means that stream levels are rising or expected to rise rapidly. No major flooding is expected, but minor flooding in low-lying areas is possible. If you are using an affected river or are located close to an affected river (camping, fishing, boating etc.), be cautious of the rising levels.

Flood watch
A flood watch means that stream levels are rising and will approach or may exceed the tops of river banks.

Flood warning
Flood of areas next to rivers under a flood watch may occur, and you are advised to take appropriate precautionary measures as instructed by the authorities through our main flood site, radio or TV. A flood warning means that rising river levels will result in the flooding of some areas. If you are close to the river, take appropriate measures to avoid flood damage as instructed in our main flood site, radio or TV.

State of local emergency
If there is danger to life, great widespread risk to public and private property, or if there is a need to consolidate resources, The City of Calgary officials can declare a Local State of Emergency. This gives the Director of Emergency Management special powers to take measures to protect life and property, including ordering mandatory evacuations. A State of Local Emergency has happened twice in Calgary - 2005 and 2013.