A search and rescue operation for three people resumed Wednesday after three witnesses said Tuesday that they were swept over the 317-foot tall Vernal Falls at Yosemite National Park.

Witnesses said that a man and woman climbed over the railing in order to take pictures and slipped on wet rocks, tumbling into the Merced River.  A third man reportedly tried to rescue the couple and jumped into the water.

All three victims, witnesses said, fell into a rock-filled pool below.   Darkness forced officials to call off the search.  Witness Linda Sabo told reporters, I saw two that were holding each other and one that was floating alone through the water.  Her husband, Dean Sabo, added, And the reason that I looked was because this woman was screaming, running along the edge of the water.

Rangers closed the notoriously slippery trail, the Mist Trail, immediately.  Visitors often assume that the trail is perfectly safe while, in reality, the mist from waterfalls creates slippery conditions.   

At least eight people have died in the park this year.  Two men were killed when they were swept off of a bridge.  One man disappeared while hiking with his church group and is still missing.