El Nino, October 2015. Maps showing ocean heights, centred on the Pacific Ocean, on 31st October 2015. Blue and purple areas are lower than average and yellow, red and white areas are higher than average. Water expands as it warms and so warm areas of the ocean are higher than cool areas. The white areas across each centre are indicative of an El Nino event. El Nino effects weather systems across the world, causing drier conditions in Australia and South-East Asia, and wetter and warmer conditions in the Americas, with often dire effects for agriculture. 2015 could see a very powerful El Nino event, possibly the most powerful since 1950. Data obtained by the Ocean Surface Topography Mission (OSTM)/Jason-2 satellite.