As rescue teams continue searching for hundreds of people missing along the Nepal-China border following catastrophic floods, humanitarian organizations are mobilizing to aid survivors.

Hundreds are dead or missing after a deadly torrent of water and mud several stories high swept through communities Wednesday following a glacier collapse.

The Nepalese army has been using helicopters to rescue people because so many roads and bridges have been washed out.

Dan Hovey, vice president of emergency response at Direct Relief, which provides medicines and healthcare to disaster-struck areas, said his organization had already pre-positioned emergency supplies in Nepal for the upcoming monsoon season. That preparation has enabled Direct Relief to help quickly during these unexpected floods.

“Nepal is a very disaster-prone country,” he said. “On the disaster vulnerability indexes, it’s one of the highest – from earthquakes, floods, drought, wildfires.”

In addition to the medicines and supplies already in Nepal, Direct Relief was readying more shipments to send to Nepal Thursday, said Hovey, adding that new donations would allow the nonprofit to provide more support in the months to come.

“This is going to be a long recovery process,” Hovey said.

Responding organizations say giving cash is currently most needed to provide local agencies and nonprofits flexible funding to continue their relief efforts.

Here are some organizations aiding those on the Nepal-China border, including U.S. groups responding on the ground.

U.S.-based organizations already operating in Nepal

All Hands & Hearts, the disaster recovery nonprofit, says it is currently providing emergency relief in Nepal, where it has worked since 2015 and plans to continue its work of rebuilding schools and homes.

Catholic Relief Services, the international humanitarian agency, has partnered with Caritas Nepal to provide aid and social services, while also working to deploy its own teams to help relief efforts.

Global Giving, the support nonprofit, has launched the Nepal Flood Relief Fund that it hopes will raise $1.5 million to provide flexible funding for search and rescue efforts and other emergency responses, as well as infrastructure rebuilding and other recovery projects.

Humanity & Inclusion, the international victim assistance nonprofit, says it is already distributing emergency supplies and providing rehabilitation support inside local hospitals.

Save the Children, the international nonprofit, says it is already delivering cooking kits, mosquito nets and blankets to 1,000 households in the region and coordinating with national and local authorities to determine how to scale its response.