With warm summer weather bringing more people and pets to the shoreline, residents are reminded to check current water advisories before swimming, boating or allowing animals to enter lakes and other recreational waters.
Local resident Cassidy Taylor Humphrey recently shared photos online expressing concern about possible blue-green algae (cyanobacteria) observed in parts of Lesser Slave Lake. At this time, no official blue-green algae advisory has been issued for Lesser Slave Lake by Alberta Health Services.
However, changing water conditions can happen quickly, and residents are encouraged to remain cautious and check for updates before entering the water.
Blue-green algae occurs naturally in many Alberta lakes and can become more noticeable during warm weather, especially when conditions allow blooms to develop. Some blooms can produce toxins that may affect people and animals.
Residents should avoid entering water that appears to have blue-green, greenish, brownish or reddish scum floating on the surface, looks like spilled paint or pea soup, contains unusual floating mats or clumps, or has a strong musty or unpleasant smell.
Exposure to toxic blue-green algae can cause skin irritation, rashes, sore throats, sore eyes, nausea, vomiting and diarrhea in people.
Pets are especially vulnerable because they may swallow large amounts of water while swimming or drinking. In animals, exposure can cause symptoms such as vomiting, weakness, difficulty breathing, seizures and, in severe cases, death.
It is also important to remember that blue-green algae is not the only possible water quality concern. Bacteria, parasites and other contaminants can affect recreational water, particularly after heavy rainfall, runoff events or periods of warm weather.
For example, Alberta Health Services has issued recreational water advisories in Alberta in response to elevated bacteria levels at some beaches.
Before heading to the lake, residents can check Alberta Health Services’ current water advisories at:
Alberta Health Services — Cyanobacteria (Blue-Green Algae) Health Advisories –
www.albertahealthservices.ca/news/bga.aspx
General public health advisories, including recreational water warnings, can also be found through:
Alberta Health Services — Active Health Advisories
www.albertahealthservices.ca/news/Page1926.aspx
Residents who have questions about water quality can also contact Alberta Health Services Environmental Public Health through Health Link at 811.
Lesser Slave Lake has experienced blue-green algae advisories in the past. In 2025, Alberta Health Services listed Lesser Slave Lake among the water bodies under a cyanobacteria advisory. The advisory was later lifted in November after cooler weather reduced the risk associated with blooms.
Lesser Slave Lake is one of the region’s greatest summer attractions, and residents are encouraged to enjoy everything the water has to offer. Before heading out, take a moment to check current advisories and be aware of what healthy water looks like. By staying informed and knowing what to watch for, residents can continue enjoying the lake safely with family, friends and pets throughout the summer.
William Hetherington
Lakeside Leader
