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 30 Mar 2025

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
Eastern Atlantic
Sao Tome and Principe	↓ Watch
Caribbean
Colombia Atlantic	↑ Watch
Nicaragua	↓ No Stress
Brazil
Buzios, Brazil	↑ Warning

Pacific Ocean
Eastern Pacific
Costa Rica Pacific	↑ Alert Level 1
Polynesia
Samoas	↑ Warning
Northern Tonga	↑ Warning
Southern Tonga	↑ Alert Level 1
Austral Islands	↓ Watch
Micronesia
Eastern FSM	↑ Watch
Melanesia
Fiji	↑ Alert Level 1
Vanuatu	↑ Alert Level 1

Southeast Asia
Other Southeast Asia Stations
Andaman, India	↑ Watch
Western Gulf of Thailand	↑ Watch
Coral Triangle
East Kalimantan	↑ Warning
Southern Borneo	↑ Warning
Maluku, Indonesia	↑ Warning
West Sulawesi	↑ Warning

Australia
Great Barrier Reef
Northern GBR	↑ Alert Level 2

Indian Ocean
South Asia
Eastern Sri Lanka	↑ Watch
Chagos Archipelago, UK	↑ Warning
Western Indian Ocean
Comoros	↓ Watch
Central Mozambique	↑ Alert Level 1
Southeastern Madagascar	↑ Alert Level 2

All Station Alert Levels

Google Earth KMZ

5-km Satellite Regional Virtual Station Bleaching Alert Details

Based on data from 30 Mar 2025



Sao Tome and Principe	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.6°C-weeks
Coral Bleaching HotSpot	0.4°C
Sea Surface Temperature (SST)	29.3°C
SST Anomaly	0.4°C
Maximum Monthly Mean SST Climatology	28.9°C
Most Recent Alert Level Changes:
03/30/2025	Watch
03/23/2025	Warning
03/19/2025	Watch
03/02/2025	Warning
01/29/2025	Watch
Map and Gauge
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Colombia Atlantic	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	28.5°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	28.7°C
Most Recent Alert Level Changes:
03/30/2025	Watch
03/26/2025	No Stress
03/16/2025	Watch
02/26/2025	No Stress
12/22/2024	Watch
Map and Gauge
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Nicaragua	↓ No Stress
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	28.1°C
SST Anomaly	0.9°C
Maximum Monthly Mean SST Climatology	28.4°C
Most Recent Alert Level Changes:
03/30/2025	No Stress
03/05/2025	Watch
01/12/2025	No Stress
12/01/2024	Watch
05/26/2024	Alert Level 2
Map and Gauge
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Buzios, Brazil	↑ Warning
Satellite Observations: (description)
Degree Heating Week	1.5°C-weeks
Coral Bleaching HotSpot	1.2°C
Sea Surface Temperature (SST)	26.7°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	25.4°C
Most Recent Alert Level Changes:
03/30/2025	Warning
03/16/2025	Watch
03/09/2025	Warning
03/02/2025	Watch
02/02/2025	No Stress
Map and Gauge
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Costa Rica Pacific	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	4.8°C-weeks
Coral Bleaching HotSpot	1.5°C
Sea Surface Temperature (SST)	30.7°C
SST Anomaly	1.6°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 1
03/05/2025	Warning
01/15/2025	Watch
12/29/2024	No Stress
12/22/2024	Watch
Map and Gauge
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Samoas	↑ Warning
Satellite Observations: (description)
Degree Heating Week	2.7°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	29.0°C
Most Recent Alert Level Changes:
03/30/2025	Warning
02/23/2025	Watch
02/05/2025	Warning
01/12/2025	Watch
12/25/2024	Warning
Map and Gauge
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Northern Tonga	↑ Warning
Satellite Observations: (description)
Degree Heating Week	2.2°C-weeks
Coral Bleaching HotSpot	1.1°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
03/30/2025	Warning
02/23/2025	Watch
02/09/2025	Warning
02/05/2025	Watch
01/26/2025	Warning
Map and Gauge
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Southern Tonga	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	6.4°C-weeks
Coral Bleaching HotSpot	1.1°C
Sea Surface Temperature (SST)	28.4°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	27.8°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 1
02/26/2025	Watch
02/12/2025	Alert Level 1
01/19/2025	Warning
12/18/2024	Watch
Map and Gauge
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Austral Islands	↓ Watch
Satellite Observations: (description)
Degree Heating Week	19.9°C-weeks
Coral Bleaching HotSpot	0.5°C
Sea Surface Temperature (SST)	25.6°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	26.3°C
Most Recent Alert Level Changes:
03/30/2025	Watch
02/12/2025	Alert Level 2
02/02/2025	Alert Level 1
01/19/2025	Warning
12/29/2024	Watch
Map and Gauge
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Eastern FSM	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.4°C
SST Anomaly	0.5°C
Maximum Monthly Mean SST Climatology	29.1°C
Most Recent Alert Level Changes:
03/30/2025	Watch
03/26/2025	No Stress
12/22/2024	Watch
08/18/2024	Alert Level 2
07/28/2024	Alert Level 1
Map and Gauge
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Fiji	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	5.8°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	28.5°C
SST Anomaly	1.4°C
Maximum Monthly Mean SST Climatology	28.4°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 1
03/26/2025	Watch
03/19/2025	Alert Level 1
03/09/2025	Watch
02/19/2025	Alert Level 1
Map and Gauge
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Vanuatu	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	5.1°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	28.6°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 1
03/16/2025	Watch
02/23/2025	Alert Level 1
02/12/2025	Watch
02/05/2025	Alert Level 1
Map and Gauge
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Andaman, India	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	29.9°C
Most Recent Alert Level Changes:
03/30/2025	Watch
11/10/2024	No Stress
11/03/2024	Watch
10/27/2024	No Stress
10/13/2024	Watch
Map and Gauge
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Western Gulf of Thailand	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.1°C
Sea Surface Temperature (SST)	30.4°C
SST Anomaly	0.7°C
Maximum Monthly Mean SST Climatology	30.1°C
Most Recent Alert Level Changes:
03/30/2025	Watch
11/24/2024	No Stress
11/17/2024	Watch
11/10/2024	No Stress
09/29/2024	Watch
Map and Gauge
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East Kalimantan	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.3°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	29.8°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	29.1°C
Most Recent Alert Level Changes:
03/30/2025	Warning
12/25/2024	Watch
12/18/2024	Alert Level 1
12/11/2024	Watch
11/17/2024	Alert Level 1
Map and Gauge
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Southern Borneo	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.1°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	30.1°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	29.3°C
Most Recent Alert Level Changes:
03/30/2025	Warning
12/25/2024	Watch
12/18/2024	Alert Level 1
12/15/2024	Watch
12/01/2024	Alert Level 1
Map and Gauge
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Maluku, Indonesia	↑ Warning
Satellite Observations: (description)
Degree Heating Week	2.6°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	30.1°C
SST Anomaly	1.3°C
Maximum Monthly Mean SST Climatology	29.1°C
Most Recent Alert Level Changes:
03/30/2025	Warning
03/23/2025	Watch
03/16/2025	Warning
02/05/2025	Watch
01/12/2025	Alert Level 2
Map and Gauge
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West Sulawesi	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.4°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	30.1°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	29.2°C
Most Recent Alert Level Changes:
03/30/2025	Warning
03/19/2025	Watch
03/12/2025	Warning
12/15/2024	Watch
11/13/2024	Warning
Map and Gauge
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Northern GBR	↑ Alert Level 2
Satellite Observations: (description)
Degree Heating Week	8.9°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	1.9°C
Maximum Monthly Mean SST Climatology	28.7°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 2
03/19/2025	Watch
03/09/2025	Alert Level 2
03/02/2025	Watch
02/09/2025	Alert Level 2
Map and Gauge
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Eastern Sri Lanka	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.3°C
Sea Surface Temperature (SST)	30.4°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	30.1°C
Most Recent Alert Level Changes:
03/30/2025	Watch
11/17/2024	No Stress
10/30/2024	Watch
08/21/2024	No Stress
08/14/2024	Watch
Map and Gauge
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Chagos Archipelago, UK	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.1°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	29.0°C
Most Recent Alert Level Changes:
03/30/2025	Warning
02/19/2025	Watch
01/29/2025	No Stress
10/06/2024	Watch
07/28/2024	No Stress
Map and Gauge
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Comoros	↓ Watch
Satellite Observations: (description)
Degree Heating Week	1.1°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	0.8°C
Maximum Monthly Mean SST Climatology	29.2°C
Most Recent Alert Level Changes:
03/30/2025	Watch
03/09/2025	Warning
02/26/2025	Watch
02/19/2025	Warning
11/24/2024	Watch
Map and Gauge
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Central Mozambique	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	7.7°C-weeks
Coral Bleaching HotSpot	1.1°C
Sea Surface Temperature (SST)	29.6°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.6°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 1
03/19/2025	Watch
02/23/2025	Alert Level 1
01/22/2025	Warning
01/05/2025	Watch
Map and Gauge
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Southeastern Madagascar	↑ Alert Level 2
Satellite Observations: (description)
Degree Heating Week	18.2°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	28.7°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	27.2°C
Most Recent Alert Level Changes:
03/30/2025	Alert Level 2
03/23/2025	Watch
02/05/2025	Alert Level 2
01/22/2025	Alert Level 1
01/01/2025	Warning
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

31-Mar-2025

Eastern Atlantic

Caribbean

Brazil

Eastern Pacific

Polynesia

Micronesia

Melanesia

Other Southeast Asia Stations

Coral Triangle

Great Barrier Reef

South Asia

Western Indian Ocean