The death toll from floods and mudslides over the past two weeks reached nearly 720 as hundreds of thousands of people remained in evacuation shelters because it was still unsafe to return home.

Stagnant water for those who stayed in flooded communities is posing a serious health threat, according to a U.N. relief official.

It is estimated that it could take up to three months for floodwaters to finally dry up.

"We need to find a way to get rid of these stagnant waters faster than waiting for them to simply evaporate," said United Nations Undersecretary General for Humanitarian Affairs and Emergency Relief Coordinator John Holmes. "The floodwaters are getting dirtier and more dangerous as time moves on."

The country’s agriculture department on Tuesday placed crop damages due to the inundations at about $250 million.

Skies remained mostly cloudy over the disaster zone until Sunday, when NASA’s Aqua satellite passed overhead.

The upper-right portion of the image to the right is from that pass on October 11. The lower portion was captured by NASA's Terra satellite the following day. The composite image shows many of the flooded waterways across Luzon Island, as well as streams of silt-rich runoff that were flowing into the ocean.

The enlarged image shows what vast parts of the region still remained deeply submerged well over a week after slowly moving Typhoon Parma finally departed. Hundreds of thousands of acres of rich farmland in the Tarlac River basin, northwest of Manila, were covered by floodwater. The former U.S. Clark Air Force Base is in this region.

Runoff from the flood zone can be seen spilling southward into Manila Bay. Similar flooding is apparent hroughout the Agno River basin to the north while the Cagayan River and its tributaries remained out of their banks.

To the southeast of Manila, the “W”-shaped Lago de Laguna shows up clearly due to the high silt content of floodwaters that had reached the huge lake.

Full story and image: NASA