The NINO3.4 index is one of several El Niņo/Southern Oscillation (ENSO) indicators based on sea surface temperatures.
NINO3.4 is the average sea surface temperature anomaly in the region bounded by 5°N to 5°S, from 170°W to 120°W. This region has large variability on El Niņo time scales, and is close to the region where changes in local sea-surface temperature are important for shifting the large region of rainfall typically located in the far western Pacific.
An El Niņo or La Niņa event is identified if the 5-month running-average of the NINO3.4 index exceeds +0.4°C for El Niņo or -0.4°C for La Niņa for at least 6 consecutive months.
The destructive core of Cyclone Debbie is already being felt along the north Queensland coastline, with the eye of the slow-moving category four storm passing over Hayman Island and hurricane-force winds battering the Whitsunday Islands.
International Space Station astronauts and NASA have captured incredible images of the size and fury of Cyclone Debbie off the coast of north Queensland.
Cyclone Debbie's eye wall reaches the North Queensland coast, bringing with it the system's strongest winds and heaviest rainfall.