Question: Why did a part of the wall fall in August 2012 in Hebei?
About the article "Great Wall of China", section "Condition".

Candidate passages:
 Hebei Provincial Museum  
Hebei Zhongji was found on 28 May 2010 by Hebei FA and Hebei Zhongji Group.
They registered to play within China League Two, third tier of the Chinese football league system, as Hebei Yilinshanzhuang (Simplified Chinese: 河北依林山庄) for sponsorship reason in the 2011 league season.
They failed to advance into the Play-offs after finishing 5th place in the group stage.
On 17 October 2011, the cooperation relationship between Hebei FA and Hebei Zhongji Group terminated, the club was totally owned by Hebei Zhongji Group and the players who owned by Hebei FA splitted into a new team, Hebei Youth.
In the 2012 league season, Hebei Zhongji were deemed as the hottest club of promotion.
They finished 1st place in North Group with 18 wins, 5 draws and only 1 defeat.
However, Hebei Zhongji were knocked out for away goals rule in the quarter-finals of Play-offs by Hubei Huakaier 1-1 on aggregate.  
Most of central and southern Hebei lies within the North China Plain.
The western part of Hebei rises into the Taihang Mountains (Taihang Shan), while the Yan Mountains (Yan Shan) run through northern Hebei, beyond which lie the grasslands of Inner Mongolia.
The Great Wall of China cuts through northern Hebei from east to west as well, briefly entering the border of Beijing Municipality, and terminates at the seacoast of Shanhaiguan in northeastern Hebei.
The highest peak is Mount Xiaowutai in northwestern Hebei, with an altitude of 2882 m. Hebei borders Bohai Sea on the east.
The Hai He watershed covers most of the province's central and southern parts, and the Luan He watershed covers the northeast.
Not counting the numerous reservoirs to be found in Hebei's hills and mountains, the largest lake in Hebei is Baiyangdian, located mostly in Anxin County.
Hebei has a continental monsoon climate, with cold, dry winters, and hot, humid summers.
Temperatures average in January and in July; the annual precipitation ranges from , concentrated heavily in summer.
Major cities:  Shijiazhuang  Baoding  Tangshan  Qinhuangdao  Handan  Zhangjiakou  
While some portions north of Beijing and near tourist centers have been preserved and even extensively renovated, in many locations the Wall is in disrepair.
Those parts might serve as a village playground or a source of stones to rebuild houses and roads.
Sections of the Wall are also prone to graffiti and vandalism.
Parts have been destroyed because the Wall is in the way of construction.
More than of the wall in Gansu province may disappear in the next 20 years, due to erosion from sandstorms.
In places, the height of the wall has been reduced from more than to less than .
The square lookout towers that characterize the most famous images of the wall have disappeared completely.
Many western sections of the wall are constructed from mud, rather than brick and stone, and thus are more susceptible to erosion.
In August 2012, a section of the wall in north China's Hebei province collapsed after days of continuous heavy rains.
Shahe () is a county-level city in the prefecture-level city of Xingtai, in the southern part of Hebei province of the People's Republic of China.