Harmful Algal Bloom Program

• Program Background
• Current Advisories (Spring-Summer)
• Nevada HAB Dashboard
• Recreational Health Advisory Levels, Exposure & Reporting
• Join the email list
• Resources & FAQ

Program Background

The Harmful Algal Bloom (HAB) Monitoring Program is implemented by several state agencies to carry out the responsibilities and procedures outlined in the HAB Strategic Response Plan (SRP).

These agencies include, but are not limited to: 

• Nevada Division of Environmental Protection (NDEP)
• Nevada Division of State Parks (NDSP)
• Nevada Division of Wildlife (NDOW)
• Nevada Department of Agriculture (NDA)
• Nevada Office of State Epidemiology (OSE)

The task force executes the HAB Monitoring Program goals through regular monitoring, sampling, and interagency communication. Monitoring and sampling consists of visual assessment in the field, desktop analyses of satellite data, and laboratory analysis of water samples. Monitoring and sampling are typically conducted during spring through summer months.

Harmful Algal Blooms (HABs) are caused by microscopic organisms called cyanobacteria, often referred to as blue-green algae. Some cyanobacteria can produce toxins that are harmful to humans and animals. Environmental factors that contribute to the formation of cyanobacterial blooms in freshwater systems include:

• light availability
• water temperature
• alteration of water flow
• vertical mixing
• pH changes
• nutrient loading (nitrogen and phosphorus)
• trace metals

When environmental conditions are favorable, rapid growth of cyanobacteria can result in HABs and may impact public health and aquatic ecosystems. A HAB may be present if:

• Water smells rotten, looks like green paint or bright colors like blue, green, white, brown, or red
• Large mats or scums are floating on the surface,
• HABs may not be visible to the naked eye and the water may still contain hazardous toxins. You can check for Nevada issued swimming advisories on the Nevada HAB Dashboard. You may also view up-to-date HAB data before visiting water bodies.

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Current Advisories (Spring through Summer)  

Please subscribe to the email list to receive weekly HAB updates via email. 

WEEKLY REPORT- PAUSED TILL SPRING 2025 NDEP releases a Weekly HAB Update with the most recent data and health advisories
ADVISORY REMOVALS:	Lahontan Reservoir - the HAB Advisory have been lifted based on cyanotoxin concentrations remaining below the HAB Watch Advisory Thresholds and absence of visual indicators of HABs.
	Lake Mohave - based on visual and analytical data the HAB Watch Advisory remains in effect.
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The Office of State Epidemiology Harmful Algae Bloom Dashboard

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Recreational Health Advisory Levels, Exposure & Reporting 

For information regarding HABs exposures and associated health effects, please review the Guidance for HABs in Nevada Brochure (PDF).

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HABs Email list

For weekly updates on HAB data and health advisories, please join the Nevada HABs e-mail list at the bottom of this webpage by clicking "Get Notices" and selecting "Nevada Harmful Algal Bloom Updates" from the dropdown menu, or you can send an e-mail directly to NEVADAHABS-subscribe-request@LISTSERV.STATE.NV.US

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Resources & Frequently Asked Questions 

• Nevada HAB Dashboard
• Strategic Response Plan (PDF)
• Recreational Threshold Advisory Rationale (PDF)
• Guidance for HABs in Nevada Brochure (PDF)
• Health Advisory Signs (PDF)
• Be Algae Aware poster (PDF)
• Frequently Asked Questions PDF
• Downloadable HAB Flow Chart (PNG)

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