Typhoon Roke has been weakened to a tropical storm, after making its landfall near central Japan early Wednesday. 　　The heavy rains and floods have been blamed for the lives of four people and the whereabouts of 3 others. 　　Following the devastating earthquake and tsunami, which battered the country in March, people are concerned that the downpours may force radioactive water into the sea, with the engineers still struggling to keep the Fukushima nuclear plant under control. 　　Hundreds of flights have been cancelled, and students were sent home early, because of the natural disaster.