The recent landslides that happened in Southern California causing millions of dollars in damage and killing 13 people could have been identified ahead of time using a new method developed by NASA’s Goddard Space Flight Center.

The model has the ability to look at landslide threats triggered by rainfall anywhere in the world in real-time from space.

If conditions beneath Earth’s surface are already unstable, heavy rains act as a “last straw” to cause mud, rocks or debris to move rapidly down mountains or hillsides. The model increases the understanding of where and when landslide hazards are present and improve estimates of long-term patterns.

"Landslides can cause widespread destruction and fatalities, but we really don't have a complete sense of where and when landslides may be happening to inform disaster response and mitigation," said Dalia Kirschbaum, a landslide expert at Goddard and lead in the research. "This model helps pinpoint the time, location and severity of potential landslide hazards in near real-time all over the globe. Nothing has been done like this before."

The mode first identifies areas with heavy, persistent and recent rainfall provided by a multi-satellite product developed by NASA using the NASA and Japan Aerospace Exploration Agency’s Global Precipitation Measurement (GPM) mission. This gives estimates of precipitation around the world every 30 minutes. The model then considers when GPM data exceeds a critical rainfall threshold looking back at the last seven days.

Where rainfall is unusually high, the model then uses a susceptibility map to determine if the area is prone to landslides. This uses five features that play a role in landslide activity, including: if roads have been built nearby, if trees have been removed or burned, if a major tectonic fault is near, if the local bedrock is weak or if hillsides are steep.

"The model has been able to help us understand immediate potential landslide hazards in a matter of minutes," said Thomas Stanley, a landslide expert with the University's Space Research Association at Goddard. "It also can be used to retroactively look at how potential landslide activity varies on the global scale seasonally, annually or even on decadal scales in a way that hasn't been possible before."