The rainfall over the Red Sea and its coasts is extremely low, averaging per year. The rain is mostly short showers, often with thunderstorms and occasionally with dust storms. The scarcity of rainfall and no major source of fresh water to the Red Sea result in excess evaporation as high as per year and high salinity with minimal seasonal variation. A recent underwater expedition to the Red Sea offshore from Sudan and Eritrea found surface water temperatures in winter and up to in the summer, but despite that extreme heat, the coral was healthy with much fish life with very little sign of coral bleaching, with only 9% infected by "Thalassomonas loyana", the 'white plague' agent. "Favia favus" coral there harbours a virus, BA3, which kills "T. loyana".