The Wyoming Department of Health (WDH) works cooperatively with the Wyoming Department of Environmental Quality to issue recreational use advisories 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. HCBs may also pose a health risk to animals. The WDH is working directly with resource management agencies to ensure signs are posted at the reservoir. Additional details regarding advisories and other HCB resources can be found at WyoHCBs.org.
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for GLENDO RESERVOIR: SANDY BEACH DUNE CAMPGROUND.
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for BOYSEN RESERVOIR: TOUGH CREEK CAMPGROUND.
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for BOYSEN RESERVOIR: MARINA CAMPGROUND.
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for BOYSEN RESERVOIR: NORTH SWIM BEACH.
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for WIND RIVER: UPPER CAMPGROUND.
A harmful cyanobacteria bloom (HCB) recreational use BLOOM ADVISORY has been issued for WIND RIVER: UPPER CAMPGROUND.
Bloom advisories are issued when a HCB is present and cyanotoxins may be present. Toxin advisories are issued when cyanotoxins exceed recreational thresholds. Waterbodies under an advisory are not closed since HCBs may only be present in certain areas and conditions can change frequently. Advisories will remain in place until blooms have fully dissipated and cyanotoxin concentrations are below recreational use thresholds identified in Wyoming’s HCB Action Plan.
If you encounter a potential HCB, the Wyoming Department of Health and the Wyoming Livestock Board recommend the following:
- Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scums.
- Do not ingest water from the bloom. Boiling, filtration and/or other treatments will not remove toxins.
- Rinse fish with clean water and eat only the fillet portion.
- Avoid water spray from the bloom.
- Do not allow pets or livestock to drink water near the bloom, eat bloom material, or lick fur after contact.
- If people, pets, or livestock come into contact with a bloom, rinse off with clean water as soon as possible and contact a doctor or veterinarian.
Questions about health effects and recreational use advisories can be directed to Courtney Tillman, Surveillance Epidemiologist, Wyoming Department of Health, at courtney.tillman@wyo.gov or (307) 777-5522. Questions regarding cyanobacteria sampling can be directed to Rachel Eyres, Recreational Water Quality Coordinator, Wyoming Department of Environmental Quality, at rachel.eyres@wyo.gov or (307) 777-2073.
Current HCB Recreational Use Advisories (Fremont County areas in bold)*Waterbody Name Observation or Sampling Location(s) Advisory Type Date Issued Alcova Reservoir Okie Beach Bloom 8/12/2025 Bighorn Reservoir Horseshoe Bend Beach Bloom 9/3/2025 Boysen Reservoir Brannon Ramp Bloom 6/23/2025 Boysen Reservoir Tough Creek Campground Toxin 9/16/2025 Boysen Reservoir Marina Campground Toxin 9/16/2025 Boysen Reservoir North Swim Beach Toxin 9/16/2025 Brooks Lake Campground Bloom 7/24/2025 Buffalo Bill Reservoir Bartlett Beach Bloom 9/3/2025 Diamond Lake (Bosler Reservoir) Northwest Access Bloom 7/30/2025 Diamond Lake (Bosler Reservoir) Northwest Access Toxin 8/5/2025 Flaming Gorge Reservoir Firehole Beach Bloom 8/7/2025 Fontenelle Reservoir East Shore Bloom 7/28/2025 Glendo Reservoir Custer Cove Campground Bloom 7/23/2025 Glendo Reservoir Sandy Beach Dune Campground Toxin 9/16/2025 Goshen Hole Reservoir Northwest Campground Bloom 7/23/2025 Granite Springs Reservoir West Causeway Bloom 8/5/2025 Grayrocks Reservoir Southwest boat ramp Bloom 5/13/2025 Guernsey Reservoir Sandy Point Campground Bloom 8/19/2025 Guernsey Reservoir Sandy Point Campground Toxin 8/19/2025 Hawk Springs Reservoir Northwest Ramp Bloom 8/20/2025 High Savery Reservoir Shore Bloom 8/4/2025 Leazenby Lake South Access Bloom 7/30/2025 Leazenby Lake South Access Toxin 8/5/2025 Little Soda Lake Shore Bloom 5/12/2025 Lower North Crow Reservoir South Shore Bloom 6/10/2025 Luckey Pond Shore Bloom 7/18/2025 McKenzie Lake Dog Park Shore Bloom 8/19/2025 McKenzie Lake Dog Park Shore Toxin 8/19/2025 Miller Lake Northeast Shore Bloom 8/21/2025 New Cody Reservoir Southwest Shore Bloom 8/29/2025 Ocean Lake Long Point Ramp Bloom 8/12/2025 Pathfinder Reservoir Bishops Point Ramp Bloom 7/15/2025 Pathfinder Reservoir Bishops Point Ramp Toxin 8/19/2025 Pelham Lake Shore Bloom 8/4/2025 Perry N Boday Lake Northeast Inlet Bloom 9/15/2025 Rainbow Lake (N of Hwy 26) Shore Bloom 8/7/2025 Saratoga Lake West Central Beach Bloom 7/30/2025 Seminoe Reservoir South Red Hills Ramp Bloom 8/14/2025 Sloans Lake South Beach Bloom 8/7/2025 Upper Brooks Lake Shore Bloom 8/7/2025 Viva Naughton Reservoir East Ramp Bloom 7/1/2025 Wheatland Reservoir #1 East Shore Bloom 6/18/2025 Wheatland Reservoir #3 Northwest Ramp Bloom 7/17/2025 Wind River Upper Campground Toxin 9/16/2025 Wind River Upper Campground Bloom 9/16/2025 Wind River Lake Shore Bloom 9/5/2025 Woodruff Narrows Reservoir North Ramp Bloom 7/1/2025 Woodruff Narrows Reservoir North Ramp Toxin 8/5/2025
*There may be additional waterbodies with HCBs that WDH and WDEQ are not aware of. Please report potential blooms to WDEQ and HCB-related illnesses to WDH.