Per the Wyoming Department of Environmental Quality, harmful cyanobacteria bloom (HCB) recreational use Toxin Advisories have recently been issued for the following areas:
A harmful cyanobacteria bloom (HCB) recreational use TOXIN ADVISORY has been issued for WIND RIVER: BELOW DAM
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 BLUE LAKE (WIND RIVER RANGE)
A harmful cyanobacteria bloom (HCB) recreational use BLOOM ADVISORY has been issued for DIAMOND LAKE (BOSLER RESERVOIR)
A harmful cyanobacteria bloom (HCB) recreational use BLOOM ADVISORY has been issued for LEAZENBY LAKE
A harmful cyanobacteria bloom (HCB) recreational use BLOOM ADVISORY has been issued for FLAMING GORGE RESERVOIR
The Wyoming Department of Health (WDH) works cooperatively with the Wyoming Department of Environmental Quality to issue recreational use advisories when cyanobacteria cell densities or cyanotoxin concentrations pose a risk to people engaging in swimming or similar water contact activities in areas where cyanobacteria 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.
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. Bloom advisories will remain in place until blooms have dissipated, and toxin advisories will remain in place until cyanotoxin concentrations are below recreational use thresholds, as 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 Cori Herzberger, Epidemiologist, Wyoming Department of Health, at cori.herzberger@wyo.gov or (330) 979-0846. 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*
| Waterbody Name | Observation or Sampling Location(s) | Advisory Type | Date Issued |
| Alcova Reservoir | Black Beach and Kids Beach | Bloom | 8/12/2026 |
| Beck Lake | Dog Park | Bloom | 7/9/2026 |
| Bighorn Reservoir | Horseshoe Bend Beach | Bloom | 7/9/2026 |
| Big Sandy Reservoir | Southeast Shore | Bloom | 7/17/2026 |
| Blue Lake (Wind River Range) | Shore | Bloom | 9/4/2026 |
| Boysen Reservoir | Fremont Bay Campground | Toxin | 8/18/2026 |
| Boysen Reservoir | Marina Campground | Toxin | 8/18/2026 |
| Boysen Reservoir | Tamarask Campground | Toxin | 8/18/2026 |
| Boysen Reservoir | Tough Creek Campground | Toxin | 8/18/2026 |
| Boysen Reservoir | Tamarask Campground | Bloom | 7/13/2026 |
| Brooks Lake | Outlet | Bloom | 7/21/2026 |
| Deaver Reservoir | Northeast Shore | Bloom | 8/28/2026 |
| Diamond Lake (Bosler Reservoir) | Northwest Access | Bloom | 9/4/2026 |
| Flaming Gorge Reservoir | Firehole Ramp | Bloom | 9/4/2026 |
| Fontenelle Reservoir | West Central Ramp | Bloom | 8/27/2026 |
| Glendo Reservoir | Custer Cove Campground | Bloom | 7/16/2026 |
| Goshen Hole Reservoir | Northwest Campground | Bloom | 8/12/2026 |
| Grayrocks Reservoir | East Central Boat Ramp | Bloom | 7/2/2026 |
| Guernsey Reservoir | Black Canyon Cove Campground | Bloom | 6/19/2026 |
| Hawk Springs Reservoir | Northwest Ramp | Toxin | 8/11/2026 |
| Hawk Springs Reservoir | Northwest Ramp | Bloom | 8/6/2026 |
| High Savery Reservoir | Shore | Bloom | 7/2/2026 |
| Leazenby Lake | South Access | Bloom | 9/4/2026 |
| Little Soda Lake | Shore | Bloom | 7/13/2026 |
| McKenzie Lake | Dog Park Shore | Bloom | 7/16/2026 |
| Miller Lake | Shore | Bloom | 7/31/2026 |
| Ocean Lake | Long Point Ramp | Bloom | 8/28/2026 |
| Pathfinder Reservoir | Bishops Point | Bloom | 7/16/2026 |
| Saratoga Lake | West Central Beach | Bloom | 7/28/2026 |
| Sloans Lake | South Beach | Bloom | 8/4/2026 |
| Sodergreen Lake | Shore | Bloom | 8/17/2026 |
| South Worland Pond | Shore | Bloom | 5/26/2026 |
| V Lake | Shore | Bloom | 7/31/2026 |
| Viva Naughton Reservoir | Northwest Campground | Bloom | 8/27/2026 |
| Wheatland Reservoir #1 | Northwest Ramp | Toxin | 8/11/2026 |
| Wheatland Reservoir #1 | Southwest Ramp | Bloom | 7/16/2026 |
| Wheatland Reservoir #3 | South Boat Ramp | Bloom | 8/17/2026 |
| Wind River | Below Dam | Toxin | 9/4/2026 |
| Wind River | Below Dam | Bloom | 8/17/2026 |
| Wind River | Upper Campground | Toxin | 9/4/2026 |
| Wind River | Upper Campground | Bloom | 9/4/2026 |
| Wind River Lake | Shore | Bloom | 7/30/2026 |
| Woodruff Narrows Reservoir | West Shore | Bloom | 8/12/2026 |
*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.

