Anybody planning on visiting Crowley Lake in the near future should proceed with extreme caution. 

Harmful algal blooms (HAB’s) have been reported along the Lake, which pose a serious threat to visitors of the area – especially children and pets. 

Both the Lahontan Regional Water Quality Control Board and Mono County Environmental Health have urged recreational water users to exercise extreme caution in light of the discoveries.

A California State Water Boards Media Release on August 19 revealed that these harmful algal blooms have been spotted at multiple locations around Crowley Lake. 

Water samples were collected on August 4 by the Regional Board staff at the Marina and Hilton Creek Drainage locations on the southern end of the lake near Highway 395.

Subsequent lab results revealed that HAB toxins in the samples exceeded the danger trigger levels; 20 micrograms per liter were found near the Hilton Creek drainage, and 6 micrograms per liter were found at the Marina. 

According to My Water Quality California, a Tier 1 caution is advised at 0.8 micrograms per liter. A tier 2 warning is advised at 6 micrograms per liter, and a Tier 3 danger notice happens at 20 micrograms per liter. 

The blooms found at Crowley do not extend across the entire lake, however caution is advised throughout the entire area due to the fact that the concentration of cyanobacteria can vary at different locations depending on time of day.

There have been warning and danger advisories posted at the entry points to the recreation areas to alert lake visitors of the potential health risks.

The warning and danger advisories will remain in place until further notice. 

These findings follow the recent death of a Northern California family and their dog due to what appears to have been HAB exposure in the Sierra National Forest, which made national news last week. 

John Gerrish, Ellen Chung, their 1-year-old daughter Miju, and their dog were all found dead on the Savage-Lundy Trail in Devil’s Gulch near Hites Cove on Tuesday, August 17. 

Investigators believe that their deaths may be due to contact with HAB’s. 

Scientists theorize that the recent drought in the area has exacerbated the blooming of HAB’s, making the entire region more susceptible.  

HAB’s produce dermatoxins that can cause skin inflammation, itchy skin and rashes, as well as gastrointestinal distress if swallowed while swimming. 

Consuming HAB-contaminated shellfish can lead to paralytic, diarrhetic, neurotoxic, and amnesiac symptoms. 

The bloom occurring at Crowley Lake appears suspended on the water’s surface. 

In some areas, the bloom may concentrate and form a film or scum on the water surface. The color of the water may also appear discolored as bright or dark green.

It is recommended to stay out of the water completely. Visitors are advised to not even touch the water. 

Visitors should also refrain from allowing their pets to go in the water or drink from the water. They have also been advised to not eat shellfish or any other type of creature from this waterbody.

The Sheet caught up with the Los Angeles Department of Water and Power to get a statement regarding the recent findings at Crowley Lake. 

“Algae blooms are a normal occurrence for Crowley Reservoir, and the other reservoirs managed as part of the LADWP Aqueduct System. During the summer, warmer surface temperatures along with nutrient rich water creates substantial blooms. LADWP regularly monitors these conditions system wide,” was all that communications and public affairs representative Jessica Johnson had to say regarding the findings.