Why are tornadoes so deadly this year?

Associated Press : Storm science has greatly improved tornado warnings in recent years. But on 25-28 April, tornadoes killed more than 300 people in the South and Midwest. Less than a month later, a devastating tornado took more than 120 lives around Joplin, Missouri, and yesterday in Massachusetts a tornado killed four people . This year could be the deadliest year for tornadoes since 1950, based on an assessment of National Weather Service figures.There are a variety of factors that helped make this year’s twisters deadlier, writes Associated Press Reporter Randolph E. Schmid. These include La Ni&ntildea, public complacency, climate change, and urban sprawl."We thought for the longest time physical science could get us by ... that we could design out of disaster,” said meteorology professor Walker Ashley of Northern Illinois University. Now scientists are finding they need to take human nature into account.