The NOAA Coral Reef Watch (CRW) Satellite Bleaching Alert (SBA) system is an automated e-mail system designed to alert subscribers to heat stress conducive to coral bleaching at select reef locations around the globe. The system automatically delivers up-to-date information on changes in the Bleaching Alert status of the coral reef environment, as detected by CRW's daily global 5km-resolution satellite coral bleaching heat stress monitoring products. The SBA is a convenient data delivery system that allows critical information about coral bleaching heat stress to reach a user's e-mail account immediately, without the user having to manually check the CRW website.

The first SBA was launched in July 2005 as a companion product to the 24 original, operational twice-weekly global 50km Virtual Stations. These original Virtual Stations were based on CRW's heritage twice-weekly global 50km bleaching heat stress products and were expanded to include 227 stations in 2013.

Shortly after the release of CRW's version 2 daily global 5km product suite in May 2014, a new set of Regional Virtual Stations was developed and released in February 2015 to take advantage of the higher spatial and temporal resolutions of the data. In October 2016, the SBA was upgraded to provide 5km satellite observational data across the 219 Regional Virtual Stations (with 5 duplicated Stations in overlapping regions). For more information regarding the changes, please see the Regional Virtual Stations description page.

Once subscribed to the SBA system, an automated e-mail is sent when the coral bleaching heat stress level (see table below) changes at the Regional Virtual Station(s) to which the user subscribes. A sample SBA message (in HTML) can be viewed here. Recent SBA email messages issued by NOAA CRW can be viewed here. Messages incorporate information found on the daily 5km Regional Virtual Stations page, including links to time series graphs, regional images, and a history of previous bleaching alerts issued. Bleaching heat stress levels defined in the table below (updated December 15, 2023 to include the new Bleaching Alert Levels 3-5) are based on the current values of the daily global 5km Coral Bleaching HotSpot and Degree Heating Week (DHW) products.

To receive automated e-mail alerts for any or all of the Regional Virtual Stations, follow the link "Subscribe to Satellite Bleaching Alerts" at the top of this page. Once a subscription is added to the e-mail alert system, a user can view and alter selection(s) or unsubscribe from the e-mail list through the same portal. If at any time you would like to unsubscribe from the automated e-mail alert system, please visit the unsubscription page.

Reports of coral bleaching (including observations of no bleaching) are greatly appreciated. Bleaching observations can be reported to your regional network or to Coral Reef Watch.

Should you have any questions or feedback on the Satellite Bleaching Alert E-mail System, please contact coralreefwatch@noaa.gov.