BEIJING (Reuters) - Devastating rains pounded three central China provinces last weekend, adding 145 deaths to the toll of more than 1,100 dead from summer flooding, a government report said. Flooding caused by heavy rains from July 17-20 affected 21 million people in 71 counties in the provinces of Jiangxi, Hubei and Hunan, the latest flood update issued by the Ministry of Civil Affairs said. The floods also destroyed 780,000 houses and hit 1.26 million hectares of farmland and about 180,000 hectares reported total crop failure. Economic losses in the three provinces caused by the floods reached 9.2 billion yuan ($1.11 billion). Flooding caused by heavy rains from July 4-20 has swept across the normally arid northwestern province of Shannxi, killing 113 people and leaving 90,000 homeless, a Shannxi provincial official said on Thursday. The latest flooding brings the death toll to at least 1,270 people. Water levels in the river valley have remained at flood stage since late June, with torrential rains in the middle and lower reaches since July 21, causing serious flooding in the Dongting Lake area in Hunan Province and Poyang Lake in Jiangxi Province. The river valley is in the grips of the second worst flooding since 1954, with water levels in some sections surpassing record highs.