EBS STAFF
Editor’s note: This story was updated on July 31, at 11 a.m. to reflect new closure information obtained by the Gallatin City-County Health Department.
Routine monitoring of Hebgen Reservoir has confirmed the presence of anatoxin-a, a harmful algal bloom that poses risk to people, pets and livestock according to a press release from NorthWestern Energy and Healthy Gallatin. The HABS were confirmed present in the Corey Springs area of the Grayling Arm, as well as the Rainbow Point area of Hebgen Reservoir. In a July 30 press release, the Gallatin City-County Health Department announced that the area is closed for water-based activities due to high toxin levels.
HABS are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs. Not all varieties of blue-green algae are harmful but some can produce dangerous toxins. Ingestion or prolonged contact with the algal bloom may result in illness, with impacts such as muscle twitching, staggering, convulsions, paralysis and death.
Children and pets are more likely to ingest HAB infested water; Livestock and pets that drink contaminated water, or collect scum on their fur then ingest it by licking are at high risk of toxin exposure.
Blue-green algal blooms often look like pea soup, grass clippings or green latex paint, according to the press release. The algae are usually suspended in the water or appear as floating mats.
Advisory signs will be posted at public access points in the Corey Springs area of the Grayling Arm warning the public that toxic algae has been identified in the water in these areas.
NorthWestern Energy, who manages the reservoir, is monitoring the blooms and will provide updates if additional restrictions are implemented for public safety.
