Source:http://rockandice.com/articles/how-to-climb/article/1123-climber-falls-140-feet-and-lives  
       Submitted by: Rock and Ice       Date:2011-12-08
       Translator: tethys  (Contact the translator: tethys2006++gmail.com, replace ++ with @)  

       On October 16, a 29-year-old climber from the Bay Area arrived at the top of the second pitch of Members Only (5.10d), a two-pitch sport route in Owens River Valley, and prepared to descend.

       The first pitch is a very popular five-star route rated 5.10d, while the second pitch is an exhausting 5.9 that few people attempt. Together, the two pitches exceed 50 meters and can be climbed as a single route, but descending directly to the ground from the top of the second pitch is nearly impossible, even with a 70-meter rope.
       However, pressed for time, the climber did not prepare to answer the belayer’s questions. Presumably, she clipped herself “directly” to the anchor chain, untied from her rope, and threaded the rope through the top anchor (topping out). At that point, the belayer (who requested anonymity) removed the protection.
       The climber then re-tied the rope, unclipped from the anchor chain, leaned back, and fell to the ground.
       Olivia Nguyen, Holly Hansen, and Patrick O’Donnell were climbing on the nearby Mothership wall when they heard a commotion.
       “I heard an impact and looked over to see the climber free-falling,” Nguyen said. “Then her rope seemed to catch on something, and she flipped over, which slowed her fall.”
       Hansen, who helped examine the injured climber, recalled that the climber and her belayer had never climbed outdoors together before. The climber suffered a fractured pelvis and broken vertebrae, with no other life-threatening injuries. The injured climber has since returned to the Bay Area and undergone four surgeries. She remains hospitalized, hoping for a full recovery of function in her left leg.

       【Accident Analysis】

       Witnesses claim the climber intended to be lowered to the ground by the belayer after topping out, while the belayer believed she planned to descend using a personal descender.
     “There was a river (the sound of flowing water made communication difficult). It’s hard to say whether she (the climber) shouted or he (the belayer) didn’t hear,” Hansen said.
       The climber fell approximately 40 feet (about 12 meters) before the rope twisted and snagged on the top anchor, although the knotted section quickly passed through the anchor chain, it still slowed her descent over the next 100 feet (about 30 meters).

      【Preventive Measures】

         According to “Accidents in North American Mountaineering,” about 5% of recorded accidents in 2009 were related to descending. Here are two foolproof ways to prevent such incidents.
       1. Clear Communication
       Discuss your plan with your belayer before starting the climb. Will you need to be lowered? Or will you descend on your own? Is the rope long enough to reach the ground? If you need the belayer to lower you, tie a knot at the end of the rope on their side. If you plan to descend on your own, most manufacturers recommend having a backup plan, such as a prusik loop ([attach]415100[/attach], which tightens around the rope under load and can slide freely when not weighted — used as a safety backup during rappelling. — Translator’s note) just in case. Communicate with your belayer beforehand to discuss the descent plan and potential issues.
        2. Test the System
       Before unclipping from the anchor, check that the knots are correct, the rope is properly threaded through the protection, and confirm with your belayer that the rope is bearing your weight. If descending on your own, inspect the rope and gear, and tighten the rope before removing protection to ensure the entire system is under load. Following these two steps can prevent almost all descending/lowering accidents. However, any oversight in the process can lead to disaster. Remember to check every step every time.