This webpage is updated monthly with information provided by Zion National Park. The Utah Division of Water Quality does not routinely conduct HAB sampling within the Virgin River Watershed. If you have additional questions, please contact Zion National Park by calling (435) 772-3256.
This webpage is updated with information provided by Zion National Park.
Updates
Lower Virgin River:
Health Watch
Monitoring for harmful algae on March 14, 2024
Harmful algal mats (benthic cyanobacteria) may be present at multiple locations along the lower Virgin River (Springdale to Bloomington). Take caution when entering the water and recreating. If a harmful algal mat is present, avoid touching or disturbing it and keep pets and children away. Avoid primary contact recreation (swimming and submerging the head) in areas with visible harmful algal mats. Do not drink in-stream water or allow pets to do so. Learn how to identify a harmful algal mat.
Lower Virgin River:
Health Watch
Monitoring for harmful algae on November 8, 2023
Harmful algal mats (benthic cyanobacteria) may be present at multiple locations along the lower Virgin River (Springdale to Bloomington). Take caution when entering the water and recreating. If a harmful algal mat is present, avoid touching or disturbing it and keep pets and children away. Avoid primary contact recreation (swimming and submerging the head) in areas with visible harmful algal mats. Do not drink in-stream water or allow pets to do so. Learn how to identify a harmful algal mat.
North Creek (including “The Subway”):
Warning Advisory
Monitoring for harmful algae on November 8, 2023
Harmful algal mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Warning Advisory
Monitoring for harmful algae on November 8, 2023
Harmful algal mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on November 8, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Warning Advisory
Monitoring for harmful algae on November 8, 2023
Harmful algal mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Lower Virgin River:
Health Watch
Monitoring for harmful algae on October 24, 2023
Harmful algal mats (benthic cyanobacteria) may be present at multiple locations along the lower Virgin River (Springdale to Bloomington). Take caution when entering the water and recreating. If a harmful algal mat is present, avoid touching or disturbing it and keep pets and children away. Avoid primary contact recreation (swimming and submerging the head) in areas with visible harmful algal mats. Do not drink in-stream water or allow pets to do so. Learn how to identify a harmful algal mat.
North Creek (including “The Subway”):
Warning Advisory
Monitoring for harmful algae on October 24, 2023
Harmful algal mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Health Watch
Monitoring for harmful algae on October 24, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on October 24, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Lower Virgin River:
Health Watch
Monitoring for harmful algae on August 9, 2023
Harmful algal mats (benthic cyanobacteria) may be present at multiple locations along the lower Virgin River (Springdale to Bloomington). Take caution when entering the water and recreating. If a harmful algal mat is present, avoid touching or disturbing it and keep pets and children away. Avoid primary contact recreation (swimming and submerging the head) in areas with visible harmful algal mats. Do not drink in-stream water or allow pets to do so. Learn how to identify a harmful algal mat.
North Creek (including “The Subway”):
Warning Advisory
Monitoring for harmful algae on July 31, 2023
Harmful algal mats (benthic cyanobacteria) are present and producing toxins. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Health Watch
Monitoring for harmful algae on July 31, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on July 31, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Virgin River near St. George:
Health Watch
Monitoring for harmful algae on July 14, 2023
Harmful algal mats (benthic cyanobacteria) may be present in the river or adjacent canals/tributaries. Avoid touching or disturbing algal mats. Do not drink in-stream water. Take care with pets and small children and do not let them play in areas with visible algal mats.
North Creek (including “The Subway”):
Health Watch
Monitoring for harmful algae on May 25, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Health Watch
Monitoring for harmful algae on May 25, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on May 25, 2023
Harmful algal mats (benthic cyanobacteria) may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Creek (including “The Subway”):
Danger
Monitoring for harmful algae on November 4, 2022
BE CAREFUL: High levels of harmful cyanotoxins were detected! Avoid all contact with water in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
North Fork of Virgin River (including “The Narrows”):
Warning
Monitoring for harmful algae quality on November 4, 2022
BE CAREFUL: Harmful cyanotoxins were detected! Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this waterbody. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
La Verkin Creek:
Health Watch
Monitoring for harmful algae on November 4, 2022
Toxigenic cyanobacteria may be present. Avoid touching or disturbing algal mats. Avoid primary contact recreation (swimming and submerging the head) when recreating in this area. Do not drink in-stream water anywhere in the park. If you must filter water, do so directly from a spring source.
Since July 2020, the National Park Service (NPS) in Zion National Park has been monitoring harmful algal bloom (HAB) toxin production on a monthly basis at several water bodies inside the park.
Cyanobacteria and HABs in the Virgin River are different from what is commonly seen in Utah’s lakes and reservoirs. This cyanobacteria grows in mats on the bottom of the riverbed, often attached to rocks or plants. It may be brown, black, tan, or green and comes in a variety of textures.
How can I stay safe while recreating in Zion National Park?
Why are habs in zion national park dangerous?
Cyanobacteria living in the Virgin River (including “The Narrows” and other locations in Zion Canyon) may produce dangerous toxins. These toxins target the liver and nervous system and are dangerous for people and animals.
Toxins can be absorbed through eyes, nose, or mouth by swimming in contaminated water – very small or even invisible pieces of the cyanobacterial growth may contain enough toxin to cause harm.
What are the symptoms of HAB exposure?
Symptoms of toxin exposure include:
If you think you have been exposed, immediately contact the Utah Poison Control Center at (800) 222-1222.
How does Zion National Park determine exposure risk?
The NPS, DWQ, and Utah Department of Health and Human Services have worked to characterize exposure risk from HABs in the Virgin River in order to better compare toxin results to the current DWQ/DHHS HAB Guidance and Recreational Thresholds.
Zion National Park staff rely on three lines of evidence for issuing recreational advisories:
- The presence or absence of known toxin-producing cyanobacteria species.
- The presence or absence of toxins in the water body using SPATT bags.
- ‘Benthic disturbance sampling’ – a process where a water quality scientist walks along a cyanobacterial mat (imitating recreation) and then measures the concentration of toxins produced.