The nutrients in the cold water also support a food supply for large fish stocks. Warmer surface waters produce atmospheric conditions favourable for thunderstorms. These thunderstorms transfer the ocean's heat into the atmosphere producing changes in atmospheric wind flows. Initially, these changed atmospheric winds only affects the weather near the Tropics but as the event develops, changes in atmospheric flows and weather are observed far from the Tropics - including Canada. Historical records from the fishermen of South America document its occurrence over the past 400 years.
Impacts are first and most strongly noticed in tropical areas.
It typically produces drought over southeast Asia, Australia and sometimes New Zealand. It frequently produces abornally high rainfalls over South America - in places which are often very dry. It can reduce the strength of the Indian monsoon. The warm water can produce more intense Pacific hurricanes than are usual. These storms travel from the Tropics and produce heavy rainfalls, flooding and damage.