The U.N. has launched a campaign to raise $120 million in emergency funding for "life-saving" aid.
"The severity of the damage has not been conveyed in the media; there are just whole sections of the western part of the southern peninsula, of the southwestern part of Haiti, that are completely devastated," Garrett Ingoglia, the vice president of emergency response for Americares, told ABC News today. "There are places where 90 percent of infrastructure is down."
Ingoglia went on to describe scenes of complete devastation, saying, "Crops are destroyed; there is no food, not a lot of clean water."
"Côteaux basically doesn’t exist anymore," Ingoglia added of a coastal town. "It is almost entirely flattened.
"All around the tip of the peninsula, that area has gotten very little aid, you can’t drive there, helicopter is the only way to get there. Roads are closed. Food, water, medicine, everything has been impossible to get there," Ingoglia continued.
"As soon as the hurricane hit people said, 'OK, we have to be ready for cholera,' but I don’t think people expected it to come this fast or this severely," Ingoglia said. "This requires a massive humanitarian response and it hasn’t happened yet."
Even days after the hurricane, "it is difficult to access a lot of towns," Ingoglia said.
The USS Mesa Verde ship arrived in Haiti with 300 Marines and four aircraft to assist in humanitarian relief efforts yesterday. The USS Iwo Jima will also arrive later this week with 500 Marines and more aircraft.
Ingoglia added that Americares has flown almost 1,000 pounds of medicine into the country, which is in urgent need of food, clean water, and air assets to be able to distribute the supplies to areas inaccessible by car.
More medicine, especially cholera medicine, is also desperately needed, Ingoglia said.
"I feel like there is not enough attention on this disaster, the amount of resources being provided are not equivalent to the need," Ingoglia told ABC News. "People don’t seem to be focused on this enough."
On top of the immediate devastation left by the hurricane, some aid groups also worry for the possibility of a long-term famine in the country.
The U.N. country director for Haiti said that 90 percent of the crops have been destroyed in what is often referred to as the country's "bread basket."
"This harvest has been lost, we are looking at a food crisis for this year, but if we don’t get some help for the farmers and the people of Haiti, we might be looking at a much longer term food crisis," Delafield said.
Delafield echoed Ingoglia, saying that huge areas remain inaccessible. Communications are also largely down, Delafield said, adding, "Cell-phone network and internet access has been a real challenge."
"It is going to be a while before all the facts come out and we really understand how bad it is," Delafield said.
In addition, Mercy Corps has been distributing shelter kits to those who lost their homes and has begun efforts to think about longer term recovery projects.
A major earthquake in 2010 killed hundreds of thousands of people, and some areas still had not fully recovered from that disaster when Matthew hit.