a natural event such as a flood, earthquake, or tsunami that kills or injures a lot of people

Europe's 2003 heat wave claimed more than 30,000 lives, making it the continent's largest natural disaster in 50 years. 欧洲2003年的热浪夺去了3万多人的生命，这是欧洲大陆50年来最大的自然灾害。