On March 11, 2011, an earthquake struck off the coast of Japan, churning up a devastating tsunami that swept over cities and farmland in the northern part of the country and set off warnings as far away the west coast of the United States and South America. Recorded as 9.0 on the Richter scale, it was the most powerful quake ever to hit the country. As the nation struggled with a rescue effort, it also faced the worst nuclear emergency since Chernobyl; explosions and leaks of radioactive gas took place in three reactors at the Fukushima Daiichi Nuclear Power Station that suffered partial meltdowns, while spent fuel rods at another reactor overheated and caught fire, releasing radioactive material directly into the atmosphere. Japanese officials turned to increasingly desperate measures, as traces of radiation were found in Tokyo's water and in water pouring from the reactors into the ocean.
As of April 7, the official death toll had been raised to 12,600, and more than 14,700 people were listed as missing, although there may be some overlap between the two groups. The final toll is expected to reach nearly 20,000. More than 160,000 people remained housed in temporary shelters; tens of thousands of others evacuated their homes due to the nuclear crisis.