Each year Kamloops deals with the threat of flooding from the North and South Thompson Rivers. The flood potential in any given year depends on the snow pack level within watersheds and warm spring weather.
The impact of high river levels in Kamloops is substantial, with 2500 properties lying within the 20 year flood plain, and 6300 properties affected by the 200 year flood levels. Snow pack and river levels are monitored constantly, and the Thompson River Annual Flood Response has three levels of Flood Alert Activities:
Red Stage (343.80 metres and over)
Inspections are increased to once daily including weekends. Required repairs due to bank erosion are carried out; public boat launches are closed and boat traffic is limited or prohibited. Emergency road berms are installed based on forecasted river levels.
Yellow Stage (342.70 m to 343.80 m)
More frequent inspections are performed; additional storm sewer outfalls are sealed.
Green Stage (up to 342.70 m)
Full inspections and assessment of riverbank, dykes, and emergency berms is carried out weekly or bi-weekly depending on threat level. Lower elevation storm sewer outfalls are sealed. Required repairs are completed, and anticipated required resources (labour, materials, equipment) are made available.