Notice: Our website and FTP site will be inaccessible for at least 30 minutes starting at 09:00EST on January 29, 2020 for system update and maintenance. We will resume our services as soon as possible. Sorry for the inconvenience.

**Notice to Users: NOAA/NESDIS plans to discontinue all operational 50km resolution satellite coral bleaching heat stress monitoring products. They are being replaced with higher resolution 5km satellite products. 50km products to be retired and replaced with 5km products are: sea surface temperature (SST), SST Anomaly, Coral Bleaching HotSpot, coral bleaching Degree Heating Week, Bleaching Alert Area, and the Virtual Stations.

Archived data and images will still be available at https://coralreefwatch.noaa.gov.

Research-supported 5km resolution versions of the products and images are available now at: https://coralreefwatch.noaa.gov/product/5km/index.php.

A 30-day comment period is now open for users to send objections or concerns about this product retirement. Send comments to John.Sapper@noaa.gov.**

50km Bleaching Alert Area
Current coral bleaching alert area
Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart Regional crw_optw_bleachingalertarea chart
Click on the image to zoom in.

Current images: Global | E.Hem. | W.Hem. | Pacific | Caribbean | Coral Triangle


Data Formats Available

images Image Archives
Regional imagery and image archives.
Google Earth Google Earth
All of our satellite data products are available on Google Earth.
Virtual Stations 50km Virtual Stations
Imagery, graphs, ASCII data, and e-mail alerts for reef pixels around the world.
animations Animations
Data animations and downloadable animated GIF files from NOAA/NESDIS' Office of Satellite and Product Operations (OSPO).


The NOAA Coral Reef Watch (CRW) twice-weekly global 50km satellite Bleaching Alert Area product presented here outlines the areas where coral bleaching heat stress currently reaches various bleaching stress levels, based on our satellite sea surface temperature (SST) monitoring. The coral bleaching heat stress levels are defined in the table below and are based on the current values of the NOAA CRW operational 50km Coral Bleaching HotSpot and Degree Heating Week (DHW) products.

Stress Level
    Definition
    Potential Bleaching Intensity
No Stress
Bleaching Watch
Bleaching Warning
Bleaching Alert Level 1
Bleaching Alert Level 2
    HotSpot <= 0
0 < HotSpot < 1
1 <= HotSpot and 0 < DHW < 4
1 <= HotSpot and 4 <= DHW < 8
1 <= HotSpot and 8 <= DHW
    No Bleaching
 
Possible Bleaching
Bleaching Likely
Mortality Likely

Please note that locations with a current status of Bleaching Watch or No Stress recently may have been exposed to heat stress. Although these two levels classify the current environmental heat stress condition, they do not take into account the recent stress history that is measured by the 50km DHW product. When the instantaneous heat stress during the current twice-weekly time period drops to a Bleaching Watch or No Stress level from a previously higher level, this product does not present any information on accumulated heat stress during the past 12 weeks up to the previous twice-weekly period. Hence, a coral reef that is at Alert Level 2 one week may drop to Bleaching Watch or No Stress the following week. Please refer to CRW's 50km DHW product for information on accumulated heat stress during the past 12 weeks.

This product is updated twice-weekly on every Monday morning and Thursday morning, U.S. Eastern Time. CRW's methodology web page and Liu et al. 2013 provide detailed information about CRW products.

NOAA CRW has been providing near real-time global 50km (0.5 by 0.5-degree spatial resolution precisely) satellite monitoring of environmental heat stress that causes mass coral bleaching to the U.S. and international coral reef communities since 1997. Our operational 50km satellite monitoring products, including Coral Bleaching HotSpot and DHW, derived from our operational nighttime SST measured by POES AVHRR, have been very successful in detecting and monitoring the heat stress that causes mass coral bleaching.


Additional description in the 50km products tutorial.
Technical details on the methodology page and in Liu et al. 2013.