Lake Conditions and Cyanobacteria (Blue-green Algae) Updates

Blue-green Algae at Rt. 78 access (2006)

Cyanobacteria, also referred to as blue-green algae, are a common and natural component of the microscopic plants (plankton) in Lake Champlain. Some types produce natural toxins or poisons. When these algae die and break down, toxins can be released into the water. Facts about Blue-green Algae

To see if a beach or swim area is open or to check its current condition: Contact the party responsible for maintaining the beach. This may be the town, a private association, or Vermont State Parks.

Not all Vermont bays, lakes, and ponds are monitored. Be aware of changing conditions, and keep people and pets away from suspected algae blooms.

Lake Conditions

Weekly Summary: September 23, 2016

Mixed conditions with blooms reported at several Lake Champlain locations and inland waters.

As the monitoring season winds down, please watch for and avoid cyanobacteria blooms, and remember that conditions can change rapidly. Check our Tracking Map or call the local beach authority for the most recent reports.

Results from the Vermont Drinking Water Facility testing: Weekly Test Results

Lake Champlain

Main Lake

Malletts Bay

St. Albans Bay

Inland Sea

Missisquoi Bay

South Lake

Vermont Inland Waters

Other Bodies of Water

Thank you to all the volunteer monitors! Updates and data are provided in cooperation with the Department of Environmental Conservation Watershed Management Division and the Lake Champlain Committee.

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Interactive Tracking Map

Blue-green Algae map icon

Map and Season Summary: 2015 | 2014 | 2013 | 2012

The tracking map provides condition information and data as of the date of a given report. Test site observations and samples are collected once each week. Conditions can and do change. People and pets should stay away from algae blooms.

The interactive Lake Champlain status map brings together in one place environmental and public health surveillance data about cyanobacteria. The map is a data collaboration project of the Departments of Health and Environmental Conservation.

For more information:
Tel: 1-800-439-8550
Email: Environmental Health Division.

Alert Levels

The color codes on the tracking map correspond with alert levels.

Generally Safe - green
No toxic blue-green algae blooms were present along these shoreline areas. These areas should be safe for recreational uses.

Low Alert - yellow
These shoreline areas have blue-green algae at levels below bloom conditions. If toxin testing was conducted, toxin concentrations are below levels of concern for recreational use. These areas are open for recreation, but caution is advised in any areas where dense accumulations or scums are apparent.

High Alert - red
These shorelines have blue-green algae in dense scums at least in some areas. If toxin testing was conducted, toxin concentrations are at or above levels of concern for recreational use. The water is not safe for recreational use in areas that contain scums.

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Watch for and Avoid Blooms

Wind and waves can move algae around. Blooms can appear or disappear very rapidly, so conditions around the lake are likely to change over the course of the week. As always, watch for and avoid blue-green algae blooms. Report Suspected Algae Blooms Return to Top