On 18 April 2014, a serac collapsed above the Khumbu Icefall on Mount Everest, causing an avalanche of massive chunks of ice and snow which killed 16 Nepalese guides, mostly Sherpas. The 2014 avalanche is the second-deadliest disaster in Everest's history, only exceeded by avalanches in the Khumbu Icefall area a year later, on 25 April 2015, caused by a magnitude 7.8 earthquake in Nepal. In response to that tragedy and others involving deaths and injuries sustained by Sherpas hired by climbers, and the lack of government support for Sherpas injured or killed while providing their services, some Sherpa climbing guides walked off the job, and some climbing companies are no longer providing guides and porters for Everest expeditions.