Blue-Green Algae Bloom at Prior Lake

May 26, 2022 (updated Sep 27, 2022, 12:23pm)

As of September 27, the advisory has been lifted at Lower Thetis Lake. However, the advisory for Prior Lake is still in effect at this time.

The blue-green algae advisory is now lifted for Lower Thetis Lake, located in Thetis Lake Regional Park. Water samples collected indicated a “below detection limit” result for cyanotoxins.

However, please note that there is still an active blue-green algae advisory in effect for Prior Lake at this time, also located within Thetis Lake Regional Park.

Park users are reminded to watch for the distinctive blue-green sheen that can appear on the lake surface at any time. These blue-green algae are known toxin producers. Ingesting water containing the blue-green algae may cause a range of symptoms, including headaches and abdominal pain in humans, and can lead to lethal liver damage in dogs.

Please visit and Twitter @crd_bc for updates on active alerts. To learn more about blue-green algae visit our website.