Coral Bleaching Alert Area (7-Day Max)

Identifies areas where coral bleaching thermal stress satisfies specific criteria (see below) based on NOAA Coral Reef Watch (CRW) HotSpot and Degree Heating Week (DHW) values. This bleaching alert area (BAA) is updated daily, but shows the maximum alert level of the preceding seven days, due to the high temporal variability in the daily 5-km SST and, thus, HotSpots. The compositing of BAA values results in greater methodological consistency and is more useful in management applications. The BAA provides a single, convenient tool for users to monitor recent thermal conditions.

Stress Level Definition Ecosystem Impact
No Stress HotSpot ≤ 0 n/a
Watch 0 < HotSpot < 1 n/a
Warning 1 ≤ HotSpot and 0 < DHW < 4 Possible Bleaching
Alert Level 1 1 ≤ HotSpot and 4 ≤ DHW < 8 Bleaching Likely
Alert Level 2 1 ≤ HotSpot and 8 ≤ DHW Mortality Likely