Near the Mariposa Port of Entry in Nogales, Ariz., a section of the rebar-reinforced fence between the U.S. and Mexico toppled over after heavy rains inundated the area.
The area floods regularly during the annual monsoon season, and since the city is built on rolling hills, water naturally flows toward its sister city in the U.S., bringing with it debris.
The storm began in Sonora, Mexico, on Friday and continued throughout most of the weekend. Debris from the flooding built up at the fence, eventually creating so much pressure that it toppled the wall.
Cerca de 50 metros de valla fronteriza fueron derribados por la fuerza de las aguas en la garita de Nogales Son. Mex.
"If your fencing is tight enough to catch debris, it basically becomes a dam." said John Hays, floodplain coordinator for the Santa Cruz County Flood Control District. "It's not meant to withstand those loads of water."
The fence is made of many steel beams, which are reinforced with a pole of rebar and filled with concrete. It also has floodgates, which did not open for a still unknown reason.
This section of the wall, which was built in 2011, was between 18 and 26 feet high and extended another 7 feet into the ground, the Associated Press reported.
Live in #Nogales this morning. Clean up continues after this weekend's monsoon. Part of the border fence is missing!
Shortly after the wall was knocked down, border agents were notified and deployed to the area, U.S. Border Patrol spokeswoman Nicole Ballistrea said.
Ballistrea said cameras would assist in patrolling the area, while repairs are being made on the damaged section of the fence.
Meanwhile, on the other side of Nogales, another section of the border was discovered deliberately cut, creating a hole large enough for a car to drive through.
Vehicle-sized gap cut in border fence near Nogales: http://t.co/2snY2IoLTf
On Saturday it was discovered that eight beams in the fence had been sliced through, Ballistrea said.
Cuts were made at the base of the beams and about 10 feet above the ground, the Nogales International reported.
Contractors were at the section of the fence by Monday to repair it with blow torches and metal clamps.