High Streamflow Advisory Ended
Updated 23 March 2026
What Do I Need to Know about Flooding in Merritt?
Merritt is situated at the confluence of the Coldwater and Nicola rivers. While flood events are rare, both rivers are capable of flooding. The Coldwater River is more likely to flood as a result of an atmospheric river event while the Nicola River is more likely to flood during freshet season.
What Are Atmospheric Rivers?
Atmospheric rivers are corridors of water vapour that are carried out of ocean tropics and can result in significant rain and snow. “Pineapple Express” storms are a specific type of atmospheric river that originate northeast of Hawaii and frequently impact the Pacific coast of North America. Atmospheric rivers vary in intensity and most are not a cause for significant concern; however, some events can cause flooding. Atmospheric rivers occur most frequently in autumn.
What is Freshet?
Freshet refers to the rise in river levels that occurs each spring when river ice and the snowpack melts. In BC, freshet typically occurs between April and July and peaks in early June.
Hydrometric Gauges
The Water Survey of Canada uses a nationwide network of hydrometric stations to monitor river levels and discharge. When flood risk is elevated, the City of Merritt keeps a close watch on the closest upstream stations for the Coldwater and Nicola rivers:
In general, flooding becomes a concern for Merritt when the discharge level at the Coldwater River station reaches 80m³/s or the discharge level at the Nicola River station reaches 55m³/s. The 2021 Coldwater River flood saw discharge in excess of 260 m³/s before the hydrometric gauge was damaged and stopped providing updates.
BC River Forecast Centre Notifications
The BC River Forecast Centre monitors snowpack, assesses seasonal water supply and flood risk, and predicts flows in British Columbia’s rivers and streams. It produces a range of bulletins, maps and warnings to inform emergency managers and the public about current and upcoming streamflow conditions.
The River Forecast Centre uses the following warning and advisories to advise when flooding may occur:
High Streamflow Advisory
River levels are rising or expected to rise rapidly, but that no major flooding is expected. Minor flooding in low-lying areas is possible.
Flood Watch
River levels are rising and will approach or may exceed bankfull. Flooding of areas adjacent to affected rivers may occur.
Flood Warning
River levels have exceeded bankfull or will exceed bankfull imminently, and that flooding of areas adjacent to the rivers affected will result.
This River Forecast Centre map shows all active flood warnings and advisories in BC:
The CLEVER Forecast
The River Forecast Centre’s Channel Links Evolution Efficient Routing (CLEVER) model provides a ten-day forecast of river discharge and return periods. The model is particularly useful for estimating river discharge when storms are forecasted. The model is available for both the Coldwater and Nicola hydrometric stations:
- CLEVER Model Coldwater River Near Brookmere (08LG048) forecast
- CLEVER Model Nicola River at Outlet of Nicola Lake (08LG065) forecast
Where Can I Learn More?
We recommend visiting the following websites to learn more about flooding:
