When Disasters Strike Twice
Like many people across the world, we at The Rockefeller Foundation have been captivated by the news coming out of Nepal. We were truly saddened by the reports of new deaths, damage, and suffering caused by the April 25th earthquake, the strong aftershocks and second earthquake that followed, and the landslides and flooding that has ensued with the start of the monsoon.
“Disasters frequently can strike twice.”
It seemed unfair that disaster should strike so many times, just as the nation was starting to recover from the devastating earthquake. It is also important to recognize that disasters frequently can strike twice. Some natural hazards are indeed linked and tend to co-occur or occur in succession. For instance:
- Landslides frequently are triggered by earthquakes, heavy rainfall, and fire.
- Landslides in turn can trigger flooding by blocking streams and rivers, as we have seen in Nepal.
- Earthquakes can occur in swarms, or a sequence of many earthquakes in a short period of time, though this is rare. These swarms can precede volcanic eruptions.
- Tsunamis occur following strong earthquakes
- Forest disturbances, such as from wind damage, can lead to catastrophic fires and insect epidemics due to the accumulation of fuel and dead wood.
- Drought periods can frequently lead to forest and grassland fires.
More frequently, however, we see cascading effects of natural hazards, which if not managed appropriately can lead to systems failures, and a second wave of catastrophic impacts. For example:
San Francisco (1906)
Most of the city of San Francisco was destroyed in 1906 following several days of fire following a very strong earthquake. It is estimated that 90 percent of the destruction was due to the fires rather than the earthquake. The earthquake caused breaks in gas mains, and disrupted water supply, hampering efforts to fight the fires.
When natural disasters dislocate people and disrupt access to clean water and sanitation, disease outbreaks can occur and spread rapidly through concentrated populations with limited access to clean water and health services. Tragically, the cholera outbreak that occurred following the 2010 earthquake in Haiti typifies this phenomenon. This outbreak resulted in an estimated 7,000 deaths.
Fortunately these sort of system failures can be prevented. Good resilience planning not only takes into account primary hazards, but also correlated hazards and potential cascading effects. Building resilience requires understanding the nature of the hazards (and potential for compound hazards), as well as understanding how the system will react, where breakdowns might occur, and how they can be prevented. If system failure can’t be fully prevented through back-up or redundant systems, at least they can be designed to fail safely to minimize the impact and prevent further catastrophe.
Disasters needn’t strike twice if we prepare appropriately.