Advisories are issued by the Wyoming Department of Health (WDH) when cyanobacterial cell densities or cyanotoxin concentrations pose a risk to people engaging in swimming or similar water contact activities in areas where cyanobacterial blooms occur.

Advisory levels elevate with increased risk to human health. WDH issues a Bloom Advisory for waterbodies when cyanobacteria blooms are present and toxins may be present. WDH issues a Toxin Advisory for waterbodies when toxins exceed recreational thresholds. Cyanobacteria and cyanotoxin thresholds are outlined in Wyoming’s HCB Response Strategy and HCB Action Plan.

Because the extent of a harmful cyanobacterial bloom (HCB) may change rapidly or move from one area of a reservoir to another, WDH will issue an advisory for an entire reservoir unless otherwise noted. An advisory for a lake or reservoir should not be interpreted as a closure since many areas of the waterbody may not be impacted by a HCB. It is important to note that advisory thresholds may not be appropriate for domestic animals or livestock.

Questions regarding general health risks and symptoms related to cyanobacterial blooms can be referred to Dr. Courtney Tillman, Surveillance Epidemiologist, at 307-777-5822.

Advisories Map