When It Rains, It Pours: New Study Finds Extreme Snowstorms And Deluges Are Becoming More Frequent And More Severe

As our climate warms, wet areas will generally get wetter (and dry areas drier). One of the consequences of global warming is the severity and frequency of rain and snow storms — fueled by the increase moisture in the atmosphere as the air warms.

A new report released by Environment America Research & Policy Center analyzed more than 80 million daily precipitation records across the United States from 1948 through 2011. The analysis reveals that climate change is now affecting the large rain or snowstorms.

The following are highlights from the report:

  • Extreme downpours — rainstorms and snow falls … are now happening 30 percent more often on average across the contiguous United States than in 1948.
  • New England has experienced the greatest change with intense rainstorms now happening 85 percent more often than in 1948.
  • Not only are extreme downpours more frequent, but they are more intense. The total amount of precipitation produced by the largest storm in each year at each station increase by 10 percent over the period of analysis, on average across the contiguous United States.

Just like a baseball player on steroids hitting more homeruns, climate change is weather on steroids and industrial pollution if fueling the extreme weather. Though we are experiencing droughts due to the U.S. southwest and southeast drying out, precipitation is increasingly concentrated into heavy downpours space further apart.

The fingerprint of climate change can be clearly identified with the increase and severity of rain and snowstorms.

The report explains that due to humans increasing emissions of heat-trapping gasses in the atmosphere — including pollution from fossil fuels — warmer temperatures in the atmosphere cause more evaporation. With warm air sitting in the atmosphere holding more water, when it rain — it pours ultimately intensifying the water cycle.

Another finding in the report is that 43 states showed statistical “significant” increase in the frequency of extreme storms. The authors define “significant” as a high probability the trend is real based on statistical analysis. The map below identifies the regions of the U.S. and recognizes the increase in frequency of rain and snowstorms:

According to the World Metrological Organization’s provisional status report issued at the United Nations climate talks in Durban, 2011 was the 10th warmest year on record and warming than any over year with a La Nina event.


But the United States is not the only country to experience extreme rain, snow, and flooding. Australia saw the country’s worst floods since 1974. A surge of rain in Brazil caused deadly landslides north of Rio de Janerio. Rainfall during June to September’s monsoons season in Thailand was up to 80% higher than the season average according to the WMO.

It is becoming much clearer how climate change affects extreme weather.

— Matt Kasper

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