When Hurricane Maria swept across Puerto Rico on 20 September 2017, meteorologists expected it to deliver a tremendous amount of rain in a short period of time. Satellite data confirm that that is exactly what happened. This map shows satellite-based measurements of rainfall in the Caribbean near Puerto Rico. It depicts accumulations measured from the evening (local time) of 18 September 2017 to the evening of 20 September 2017. The brightest areas reflect the highest rainfall amounts, as much as 20 inches (500 millimeters) in places. The measurements are a product of the Global Precipitation Measurement (GPM) mission, which is a partnership between NASA, the Japan Aerospace Exploration Agency, and five national and international partners. Graphic: Joshua Stevens / NASA Earth Observatory

By Kerry Emanuel
19 September 2017
(The Washington Post) – As the United States struggles to recover from two back-to-back hurricanes, it would be wise to reflect on why we keep having such calamities and whether they are likely to get worse.
We must first recognize the phrase “natural disaster” for what it is: a sham we hide behind to avoid our own culpability. Hurricanes, floods, earthquakes and wildfires are part of nature, and the natural world has long ago adapted to them. Disasters occur when we move to risky places and build inadequate infrastructure.
In the United States, we have in place a range of policies that all but guarantees a worsening string of Katrinas, Sandys, Harveys, and Irmas as far as we can see into the future. Climate change acts as a threat-multiplier to these policy-generated disasters, making them progressively worse than they would have been in a stable climate.The U.S. hurricane policy disaster has its roots in the hijacking of politics by special interests. In a free market, risk is largely communicated through pricing. Smokers pay greater health insurance premiums to cover the added risk of their voluntary activity. In a rational world, premiums in hurricane-prone places would be sufficiently high to reflect the actual risk to the property.But agitation by coastal property owners has resulted in a rigged system in which states place caps on property insurance premiums, or on the maximum difference between premiums charged to risky and less risky customers, forcing the latter to subsidize the former. Hurricane storm surges and freshwater flooding are covered by the National Flood Insurance Program, and here too agitation has resulted in rates that do not adequately reflect the risk. Congress revamped this program in 2012, only to retract many of those changes in 2014 in response to a backlash from flood-prone homeowners.On top of this, federal disaster relief, as necessary as it may be, inadvertently subsidizes risk. As a consequence of these subsidies, coastal populations are rising much faster than the general population. Globally, the population exposed to hurricane hazards has tripled since 1970, and the trend shows no signs of abating.To make matters worse, climate change is increasing the probabilities of hurricane disasters in many places. Rising sea levels worsen storm surges, often the most deadly and destructive aspects of hurricanes. Sandy would probably not have flooded Lower Manhattan had it occurred 100 years earlier, when sea levels were about a foot lower in New York. [more]

Why it’s time to stop calling these hurricane disasters ‘natural’