2026 Weekly Cyanobacteria Emails to Monitors

This week, St. Albans Bay recorded one of the highest percentages of cyanobacteria bloom reports on Lake Champlain this season. These images from Hathaway Point Boat Launch show a Category 3 bloom, including the shoreline accumulation, a jar sample confirming the dense layer of cyanobacteria colonies, and a microscope view.

Lake Champlain continued to see relatively few cyanobacteria blooms this week, with just three high alerts and six low alerts reported across the lake. Pictured is one of this week's Category 3 blooms at Black Bridge in St. Albans, VT, one of only two lake regions to report high alert conditions.

After several active weeks, bloom reports declined across Lake Champlain, with 12 blooms documented and no blooms reported on Vermont's inland lakes. Although wildfire smoke created hazy conditions throughout the week, monitors continued to submit reports. The Category 3 bloom pictured above at Cedar Lane in Willsboro, NY, formed green thick streaks along the shoreline.

Volunteers submitted 201 monitoring reports this week, with nearly one in four reports documenting bloom conditions on Lake Champlain. St. Albans Bay experienced the highest percentage of blooms, while Main Lake Central received the greatest number of monitoring reports. The Category 3 bloom pictured at Button Bay Boat Launch in Ferrisburgh, VT, formed a dense green surface accumulation stretching across the nearshore waters.

Week 3 brought cyanobacteria blooms to several regions of Lake Champlain, with 14% of monitoring reports indicating bloom conditions. Missisquoi Bay recorded the highest percentage of blooms relative to the number of reports received, with one-third of montioring reports documenting bloom conditions. 

The second week of monitoring brought the season's first widespread reports of cyanobacteria blooms, with monitors documenting green surface accumulations and shoreline scums at several locations around Lake Champlain and inland lakes. The Category 3 bloom pictured above, reported from Philipsburg, Québec, formed a dense, spilled-paint-like scum that extended along the shoreline.

The first week of monitoring kicked off with rainy weather and a range of generally safe conditions around Lake Champlain - though some phenomena including turbid waters, pollen-filled shorelines, and rocky habitats coated with filamentous green algae provided a good early test in identifying circumstances that are not cyanobacteria. Thank you to our volunteer monitors for a great first week of tracking water quality across the basin.