NOAA Coral Reef Watch Satellite Bleaching Alert System (SBA)

NOAA Coral Reef Watch Satellite Bleaching Alert

5-km Satellite Regional Virtual Stations

Bleaching or no bleaching, please report to your regional network or to Coral Reef Watch!

Alert Changes Summary

Based on data from 12 Apr 2026

No Stress

Watch

Warning

Alert Level 1

Alert Level 2

(↑) or (↓) indicates an increase or decrease in the heat stress level

Alerts are for reef regions, archipelagos or jurisdictions, not for individual data grid points


Atlantic Ocean
Caribbean
Nicaragua	↑ Watch
Brazil
Todos os Santos, Brazil	↑ Alert Level 1

Pacific Ocean
Eastern Pacific
Panama Pacific West	↓ Watch
Isla del Coco, Costa Rica	↓ Watch
Polynesia
Wallis and Futuna	↑ Alert Level 1
Southern Tonga	↓ Watch
Micronesia
Palau	↑ Watch

Southeast Asia
Other Southeast Asia Stations
Great Nicobar, India	↑ Warning
Southwestern Thailand	↓ Watch
Malacca Strait, Malaysia	↑ Warning
Spratly Islands	↑ Watch
Brunei Darussalam	↑ Watch
Riau Islands	↑ Watch
Coral Triangle
Western Philippines	↑ Watch
South Sulawesi	↑ Warning
West Nusa Tenggara	↑ Warning
Timor-Leste	↑ Watch

Australia
Great Barrier Reef
Far Northern GBR	↓ No Stress
Northern Coral Sea Islands	↓ No Stress
Other Australia Stations
Shark Bay	↑ Watch

Indian Ocean
Middle East
Al Wusta, Oman	↑ Watch
Dhofar, Oman	↑ Watch
South Asia
Kerala, India	↓ Watch
Gulf of Mannar	↑ Warning
Southern Sri Lanka	↑ Warning
Western Indian Ocean
Somalia	↑ Warning
Glorioso Islands	↓ Watch
Inhambane, Mozambique	↓ Watch
Northeastern Madagascar	↓ Watch
Tromelin and Reunion, France	↓ Watch
Southeastern Madagascar	↓ Watch

All Station Alert Levels

Google Earth KMZ

5-km Satellite Regional Virtual Station Bleaching Alert Details

Based on data from 12 Apr 2026



Nicaragua	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.1°C
Sea Surface Temperature (SST)	28.3°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	28.4°C
Most Recent Alert Level Changes:
04/12/2026	Watch
12/28/2025	No Stress
11/19/2025	Watch
09/24/2025	Alert Level 2
09/07/2025	Alert Level 1
Map and Gauge
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Todos os Santos, Brazil	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	4.9°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	29.1°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	27.9°C
Most Recent Alert Level Changes:
04/12/2026	Alert Level 1
04/08/2026	Watch
03/29/2026	Alert Level 1
03/11/2026	Warning
03/04/2026	Watch
Map and Gauge
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Panama Pacific West	↓ Watch
Satellite Observations: (description)
Degree Heating Week	1.0°C-weeks
Coral Bleaching HotSpot	0.7°C
Sea Surface Temperature (SST)	29.8°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	28.9°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/29/2026	Warning
12/24/2025	Watch
12/21/2025	No Stress
12/10/2025	Watch
Map and Gauge
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Isla del Coco, Costa Rica	↓ Watch
Satellite Observations: (description)
Degree Heating Week	1.5°C-weeks
Coral Bleaching HotSpot	0.6°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	0.8°C
Maximum Monthly Mean SST Climatology	29.0°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/25/2026	Warning
03/22/2026	Watch
03/15/2026	Warning
02/11/2026	Watch
Map and Gauge
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Wallis and Futuna	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	4.2°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	30.0°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	29.1°C
Most Recent Alert Level Changes:
04/12/2026	Alert Level 1
04/05/2026	Watch
03/18/2026	Alert Level 1
03/11/2026	Watch
03/04/2026	Alert Level 1
Map and Gauge
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Southern Tonga	↓ Watch
Satellite Observations: (description)
Degree Heating Week	18.8°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	28.8°C
SST Anomaly	1.7°C
Maximum Monthly Mean SST Climatology	27.8°C
Most Recent Alert Level Changes:
04/12/2026	Watch
02/08/2026	Alert Level 2
01/25/2026	Alert Level 1
01/04/2026	Warning
12/21/2025	Watch
Map and Gauge
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Palau	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.1°C
Sea Surface Temperature (SST)	29.3°C
SST Anomaly	0.8°C
Maximum Monthly Mean SST Climatology	29.2°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/18/2026	No Stress
12/07/2025	Watch
11/30/2025	Alert Level 1
11/12/2025	Watch
Map and Gauge
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Great Nicobar, India	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.3°C-weeks
Coral Bleaching HotSpot	1.1°C
Sea Surface Temperature (SST)	30.8°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	29.5°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/04/2026	Watch
07/16/2025	No Stress
07/02/2025	Watch
06/15/2025	No Stress
Map and Gauge
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Southwestern Thailand	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.6°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	31.3°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	29.9°C
Most Recent Alert Level Changes:
04/12/2026	Watch
04/05/2026	Warning
03/01/2026	Watch
10/29/2025	No Stress
09/21/2025	Watch
Map and Gauge
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Malacca Strait, Malaysia	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.7°C-weeks
Coral Bleaching HotSpot	1.2°C
Sea Surface Temperature (SST)	31.0°C
SST Anomaly	1.4°C
Maximum Monthly Mean SST Climatology	29.9°C
Most Recent Alert Level Changes:
04/12/2026	Warning
04/05/2026	Watch
03/25/2026	Warning
02/11/2026	Watch
01/25/2026	No Stress
Map and Gauge
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Spratly Islands	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.1°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	29.7°C
Most Recent Alert Level Changes:
04/12/2026	Watch
11/26/2025	No Stress
11/16/2025	Watch
11/12/2025	No Stress
10/26/2025	Watch
Map and Gauge
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Brunei Darussalam	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.2°C
Sea Surface Temperature (SST)	30.0°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	29.7°C
Most Recent Alert Level Changes:
04/12/2026	Watch
01/07/2026	No Stress
08/17/2025	Watch
07/30/2025	Warning
06/29/2025	Watch
Map and Gauge
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Riau Islands	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.8°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	29.8°C
Most Recent Alert Level Changes:
04/12/2026	Watch
11/30/2025	No Stress
09/24/2025	Watch
09/14/2025	No Stress
09/07/2025	Watch
Map and Gauge
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Western Philippines	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.5°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	29.6°C
Most Recent Alert Level Changes:
04/12/2026	Watch
11/12/2025	No Stress
09/10/2025	Watch
09/03/2025	No Stress
07/30/2025	Watch
Map and Gauge
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South Sulawesi	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.1°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	30.2°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	29.3°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/29/2026	Watch
03/15/2026	No Stress
11/19/2025	Watch
10/29/2025	Warning
Map and Gauge
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West Nusa Tenggara	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.6°C-weeks
Coral Bleaching HotSpot	1.2°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/18/2026	Watch
03/11/2026	No Stress
03/04/2026	Watch
03/01/2026	No Stress
Map and Gauge
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Timor-Leste	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.5°C
SST Anomaly	0.6°C
Maximum Monthly Mean SST Climatology	29.5°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/08/2026	No Stress
02/11/2026	Watch
01/28/2026	No Stress
10/26/2025	Watch
Map and Gauge
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Far Northern GBR	↓ No Stress
Satellite Observations: (description)
Degree Heating Week	5.2°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.1°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
04/12/2026	No Stress
03/15/2026	Watch
02/25/2026	Alert Level 2
02/08/2026	Alert Level 1
01/18/2026	Watch
Map and Gauge
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Northern Coral Sea Islands	↓ No Stress
Satellite Observations: (description)
Degree Heating Week	4.4°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	27.8°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	28.3°C
Most Recent Alert Level Changes:
04/12/2026	No Stress
03/15/2026	Watch
02/18/2026	Alert Level 1
02/15/2026	Warning
02/11/2026	Watch
Map and Gauge
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Shark Bay	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.3°C
Sea Surface Temperature (SST)	25.2°C
SST Anomaly	0.3°C
Maximum Monthly Mean SST Climatology	25.0°C
Most Recent Alert Level Changes:
04/12/2026	Watch
04/08/2026	No Stress
03/29/2026	Watch
03/18/2026	No Stress
03/01/2026	Watch
Map and Gauge
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Al Wusta, Oman	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.5°C
Sea Surface Temperature (SST)	28.2°C
SST Anomaly	1.4°C
Maximum Monthly Mean SST Climatology	27.8°C
Most Recent Alert Level Changes:
04/12/2026	Watch
11/23/2025	No Stress
10/19/2025	Watch
07/06/2025	No Stress
06/22/2025	Watch
Map and Gauge
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Dhofar, Oman	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	28.9°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	28.3°C
Most Recent Alert Level Changes:
04/12/2026	Watch
11/12/2025	No Stress
11/02/2025	Watch
06/22/2025	No Stress
06/11/2025	Watch
Map and Gauge
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Kerala, India	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.8°C-weeks
Coral Bleaching HotSpot	0.6°C
Sea Surface Temperature (SST)	30.3°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	29.5°C
Most Recent Alert Level Changes:
04/12/2026	Watch
04/01/2026	Warning
03/11/2026	Watch
03/08/2026	No Stress
02/25/2026	Watch
Map and Gauge
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Gulf of Mannar	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.3°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	31.3°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	30.1°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/22/2026	Watch
07/27/2025	No Stress
07/13/2025	Watch
06/11/2025	No Stress
Map and Gauge
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Southern Sri Lanka	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.3°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	30.5°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	29.4°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/18/2026	Watch
11/30/2025	No Stress
11/12/2025	Watch
11/09/2025	No Stress
Map and Gauge
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Somalia	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.4°C-weeks
Coral Bleaching HotSpot	1.2°C
Sea Surface Temperature (SST)	30.0°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
04/12/2026	Warning
03/22/2026	Watch
05/18/2025	No Stress
05/14/2025	Watch
04/30/2025	Alert Level 1
Map and Gauge
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Glorioso Islands	↓ Watch
Satellite Observations: (description)
Degree Heating Week	1.4°C-weeks
Coral Bleaching HotSpot	0.5°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	0.6°C
Maximum Monthly Mean SST Climatology	28.9°C
Most Recent Alert Level Changes:
04/12/2026	Watch
04/05/2026	Warning
03/29/2026	Watch
03/22/2026	Warning
03/18/2026	Watch
Map and Gauge
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Inhambane, Mozambique	↓ Watch
Satellite Observations: (description)
Degree Heating Week	2.9°C-weeks
Coral Bleaching HotSpot	0.1°C
Sea Surface Temperature (SST)	27.8°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.0°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/22/2026	Warning
03/15/2026	Watch
03/08/2026	Warning
01/07/2026	Watch
Map and Gauge
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Northeastern Madagascar	↓ Watch
Satellite Observations: (description)
Degree Heating Week	7.5°C-weeks
Coral Bleaching HotSpot	0.3°C
Sea Surface Temperature (SST)	28.4°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	28.2°C
Most Recent Alert Level Changes:
04/12/2026	Watch
04/01/2026	Alert Level 1
03/15/2026	Watch
02/25/2026	Alert Level 1
02/18/2026	Warning
Map and Gauge
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Tromelin and Reunion, France	↓ Watch
Satellite Observations: (description)
Degree Heating Week	5.8°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	28.6°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	27.9°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/25/2026	Alert Level 1
02/22/2026	Warning
12/31/2025	Watch
12/21/2025	No Stress
Map and Gauge
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Southeastern Madagascar	↓ Watch
Satellite Observations: (description)
Degree Heating Week	9.6°C-weeks
Coral Bleaching HotSpot	0.4°C
Sea Surface Temperature (SST)	28.4°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	27.2°C
Most Recent Alert Level Changes:
04/12/2026	Watch
03/22/2026	Alert Level 2
03/01/2026	Alert Level 1
02/22/2026	Warning
02/15/2026	Watch
Map and Gauge
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Summary Notes

No Stress	No heat stress	HS <= 0
Watch	Low heat stress	0 < HS < 1
Warning	Heat stress accumulating	HS >= 1 0 < DHW < 4
Alert Level 1	Bleaching expected	HS >= 1 4 <= DHW < 8
Alert Level 2	Significant bleaching expected; mortality likely	HS >= 1 DHW >= 8

Bleaching alerts are only generated when there is a stress level change for a station.
The alerts are generated for affected reef regions, archipelagos, and/or jurisdictions, not for individual data grid points.
Your bleaching observations (including observations of no bleaching) are greatly
appreciated. Observations can be sent to coralreefwatch@noaa.gov and/or entered online via Coral Reef Watch.
Should you have any questions or feedback on our Satellite Bleaching Alert email system, please send an email to coralreefwatch@noaa.gov.
To view, change (stations, email type, etc), or end your subscription, please visit the Coral Reef Watch Satellite Bleaching Alert website.
Please do not reply to this email address.

Disclaimer

13-Apr-2026

Caribbean

Brazil

Eastern Pacific

Polynesia

Micronesia

Other Southeast Asia Stations

Coral Triangle

Great Barrier Reef

Other Australia Stations

Middle East

South Asia

Western Indian Ocean