Race Against Time: A look at Nepal Rescue Efforts

Rescue crews from around the globe are headed to Nepal in the race to provide disaster relief and pull survivors still beneath the rubble in the wake of Saturday's earthquake that toppled temples, triggered a Mt. Everest avalanche and devastated the capital of Kathmandu.

This comes as officials said today the death toll had surpassed 4,000.

The U.S. government is providing an additional $9 million in assistance, Secretary of State John Kerry said today, in addition to the $1 million already provided.

U.S. disaster relief teams are en route to join U.S. Special Forces already in Nepal. A search-and-rescue team from California took off for Nepal late Sunday night, according to the Los Angeles County Fire Department.

Crews from Israel, Japan, Australia, India, China, Germany, Canada and New Zealand are also headed to the region.

Even social media is contributing to the rescue efforts. Facebook has activated its "safety check" feature, which allows users to tell friends and family they are safe. Google has also activated its own disaster tool called "person finder" and is updating satellite imagery to help with relief efforts.

At Mt. Everest, where the magnitude-7.8 quake triggered an avalanche, three helicopters have started to rescue up to 150 stranded mountaineers. The mountain is too treacherous to walk down; the only way to evacuate safely is by helicopter.

Tents, clothing and oxygen supplies are strewn across the mountain as rescuers try to reach survivors before supplies run out or another aftershock hits. Nearly the entire 100,000-soldier Nepalese army is involved in rescue operations, the army said. Many climbers remain unaccounted for.

In Kathmandu, many streets are impassable, filled not only with rubble but with the injured. Drone footage captures the chaos in the streets as global rescue teams continue to dig through collapsed buildings in search for buried survivors.

Thousands of people are fleeing Kathmandu, unwilling to go into any building, fearing the effects of another aftershock.

The Associated Press contributed to this report.