The aftermath of the storm can be seen in before and after false-color images captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor aboard NASA's Terra satellite. ASTER snapped images in 4 April 2004 and in 15 November 2013, just days after the storm.
The aftermath photo reveals the hills were stripped bare of vegetation by winds, while the coastline is swamped by floodwater. Plant-covered land is red; urban areas are white and silver; bare ground is tan; and water and shadows are black. From ASTER’s wide perspective, it is not possible to see individual city blocks of destroyed buildings. But the subtle differences between the images do reveal a wide-scale disaster.
The most obvious difference is a change in vegetation. In 2004, the mountains west of the city were covered in dense vegetation; in 2013, the hills are bare. Nine years elapsed between the two images, and many things could explain the change. It is not certain if the people cleared the land, or the plants simply look different in November than they do in April. Since this is a tropical location where seasons have little impact, it is just as likely that Haiyan’s winds are responsible for the change. News photos of the hills show trees stripped of leaves or blown down.Near the coast, the storm's impact is more unequivocal. Much of the area south of Tacloban is tan where the storm surge washed away plants and buildings, leaving mud-covered ground. This is the clearest evidence of the storm surge. The small peninsula where Tacloban’s airport is located was one of the most severely affected parts of the city, and a close look at the image shows that this area is also brown, which means that few plants or buildings survived. Interestingly, the large geometric white shape near the airport is new compared to another satellite-based map from July 2013. The shape indicates that this is a man-made structure, perhaps associated with relief efforts at the airport.
About 800,000 people were moved to storm shelters, but Haiyan's deadly flooding reached a height of 20 feet (6 meters) in the central Philippines. Current estimates place the death toll at more than 4,000 people. Thousands remain missing and relief efforts have been hampered by the difficulty of reaching remote islands, according to news reports.
NASA scientists are using satellite imagery to produce damage maps that will help aid disaster relief efforts in the Philippines, NASA officials said.
The images give a view of the entire city and its surroundings, a view that would otherwise be very difficult to obtain. On the other hand, some of the change is ambiguous and requires ground-based information to understand.