On February 17, 2006, the Philippine village of Guinsaugon disappeared. A massive landslide swallowed more than 350 houses and an elementary school, burying more than 1,100 people. Residents of the village, situated at the foot of a mountain on Leyte Island, had no warning and no time to evacuate. While there was no direct trigger for the Guinsaugon landslide, experts and officials explored several causes, including several days of unusually heavy rainfall that had saturated the mountainside prior to the slide.
While rainfall-induced landslides can happen within minutes, the wet conditions that precede them can take several hours or days to develop. But many countries in high-risk areas lack the resources to maintain the extensive weather networks required to successfully observe these conditions. Robert Adler, a senior scientist in the NASA Laboratory for Atmospheres at Goddard Space Flight Center, and Yang Hong, a research scientist at NASA's Goddard Earth Sciences and Technology Center (GEST), approached the problem from space. A reliable satellite-based system would help minimize the challenge of maintaining local systems, especially in regions where heavy rains and flooding often wash away ground-based instruments. Adler and Hong are merging data from an array of satellites to determine whether remote sensing instruments can indicate where rainfall-induced landslides might occur. Adler said, “If we can complete this research and make the results available on the Web, then almost any government or organization in the world can access this information.”