One month after the last of a series of hurricanes devastated Haiti, medical personnel from the French NGO Doctors Without Borders discovered that Mamont, a cluster of villages, had been entirely submerged by flooding. Forgotten, 2,400 people were left without food, water or assistance for weeks. 466 people died.

“Our teams reached Mamont, in the south-west of Gonaives, on September 30. The population of this area has been completely isolated for the past four weeks,” said the NGO in a statement.

Four major storms that pounded Haiti in August and September killed 793 people and left more than 300 others missing, authorities said Friday.

Haitian Civil Protection announced the new figures in a dramatic surge upward from their previous estimate of 326 dead on September 11 after the passing of Tropical Storm Fay and hurricanes Gustav, Hanna and Ike.

According to the new data, "793 people were killed, 466 of them in the city of Gonaives alone, the hardest hit by the storms, while there are 310 people unaccounted for and 548 injured," said Civil Protection spokeswoman Alta Jean-Baptiste.

Mountainous Haiti, the poorest country in the Americas, has a major deforestation crisis as people cut down trees and bushes to cook. Heavy rains leave it especially vulnerable to mudslides and flooding.