WHEN IT DOUBT, STAY OUT! The Eau Claire City-County Health Department has officially closed Lake Altoona beach and placed a countywide beach advisory over Labor Day weekend due to harmful algae bloom activity. Tests for algae are completed weekly on the eight bodies of water in Eau Claire county: Big Falls Beach, Coon Fork Beach, Lake Altoona, Lake Eau Claire, Half Moon Lake, among others.

Locals are likely to have seen the on-and-off-again beach closure announcements from the Eau Claire City-County Health Department throughout the summer season. For Lake Altoona beach (604 S. Beach Dr., Altoona), dozens of days have been impacted due to harmful algae and sedimentation levels this year.

Now, headed into Labor Day weekend, the Eau the Eau Claire City-County Health Department has closed Lake Altoona beach once again. The department has also issued a countywide beach advisory – both announcements due to harmful algae bloom activity.

According to a media release shared Friday, Sept. 4, “Wisconsin DHS and DNR today confirmed that the Lake Altoona Beach water samples contained algae toxin levels high enough to cause significant health impacts to both humans and animals.”

This announcement comes just weeks after the state DNR told Wisconsin Public Radio it had seen more reports of blue-green algae blooms this year than at the same time in 2025.

“Some of the most common symptoms reported include stomach cramps, diarrhea, vomiting, cough, sore throat, headaches and a rash,” WPR reported. “Children tend to be most affected, and signs of illness can show up within minutes to hours after exposure.”

Eau Claire City-County Health Department Advisory / Friday, Sept. 4

The Health Department encourages locals and visitors to take extra caution* when swimming or using the water in the county's lakes and rivers over the weekend. Motorized boating should also be avoided in bodies of water with an algae bloom.

Everyone should avoid water that:

• Looks like pea soup or spilled paint

• Is discolored or has colored streaks

• Has surface scums, mats, or films

• Has green dots or globs floating beneath the surface

*If you, another person or pet develops an illness related to blue-green algae, call your doctor or the Wisconsin Poison Center (800-222-1222) and notify the Wisconsin Department of Health Services’ Division of Public Health.

Visitors and locals are encouraged to stay away from those bodies of water (algae bloom activity has also been reported by the Health Department at several other beaches this summer) under the advisory across Eau Claire county.

The DNR reported these environmental conditions stem from persistent heat and calm conditions forecast, which create an ideal habitat for bacterial growth.

Staff in the Eau Claire County Health Department will continue to monitor the water quality – routine checks increase when advisories are in place – and share updates online and via its Facebook page  when new information is available.

2026 Lake Altoona Study & Algae Blooms

This year, an online survey was sent to all landowners within the Lake Altoona District to measure lake utilization and calculate annual short-term and 5-year expenditures as a result of water contamination.

The study found Lake Altoona's growing degradation of water quality and increased sedimentation – in tandem with algae blooms – threaten the lake’s recreational value through beach closures, deteriorating the fishery and reducing boating opportunities due to decreased water depth.

Visit the Eau Claire County Health Department Facebook page (@eauclairehealth) for ongoing updates. For more information on blue-green algae contamination in Eau Claire County, review previous coverage from VolumeOne.org or the Wisconsin Department of Health Services webpage online.