Weekly Report & Winni Bloom Watch Map

Take the Survey: Impacts of Boating on Winni Wildlife and Habitat

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Take Action: Find Out How You Can Make a Difference

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Watch Now: The Value of Lake Winnipesaukee

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Job Opportunity: Communications and Conservation Program Assistant

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Cyanobacteria and Harmful Algal Blooms

If you suspect that a waterbody is experiencing a cyanobacteria bloom please notify LWA and NH DES.

The map linked below indicates Cyanobacteria advisories and sightings in the Lake Winnipesaukee watershed. The report card summarizes key information that can have an influence on cyanobacteria. The report card is updated on a weekly basis and the map is updated as needed.

 For more information about Cyanobacteria, to report a harmful algal bloom or to log pictures of your sightings (bloomWatch) please use the links below:

Reporting Information

Additional Resources

Sighting Locations: Please note that the map is meant to be used as an informational tool with approximate locations of cyanobacteria sightings. Click the points on the map for additional details. Surface blooms can rapidly change and accumulate in various locations around a waterbody. The green circles represent confirmed sightings while red circles represent advisories issued. State advisories are issued when samples are collected and identified with cell concentrations exceeding the state threshold of 70,000 cells/ml.

Click Here to View Cyanobacteria Map


Click Here to View a List of Observations and Advisories (2019-2021)