During the 2011 monsoon season in Thailand, severe flooding occurred. Over 800 people died, 77 provinces were declared disaster zones and the world bank estimated the total cost approaching 50 billion USD, ranking it as the 4th most costly disaster in the world. The flood lasted close to 6 months, from July 2011 to January 2012. Close to 15 million people were directly affected. In order to prevent further damages, accurate monitoring of the extent of the flood was required, and UNOSAT provided periodically updated flood maps based on using radar satellite images every few days for a period. The flood maps were offered publicly. Both the Thai government, the Asian Disaster Prevention Center (ADPC) and Google.org used them in their disaster management. When the flood approached the larger cities, and specifically Bangkok, a larger disaster was possible. More frequent and more accurate flood predictions were needed than in the rural areas, as much more was at stake.