Too Much Rain, No Where to Go

The photos of flooding from last night’s incredible rain bring back memories of May 1 and 2, 2010.  Fortunately there were no deaths last night or today but there was lose of property.  In northern Sumner County radar estimates near 7″ of rain. Dan Thomas showed that graphic and described the thunderstorm event last night in his afternoon blog. Click here to check it out.

Blog Inland Flooding

Station Camp Creek credit: @Angelinben88

The flooding rain last night and the recent flooding in the Gulf Coast states highlight the increasing threats from heavy rain with changes in the climate. The flooding of streams, creeks and rivers is not just dependent on heavy rain though. Land use, topography, soil saturation and the location of levees and dams all contribute in how water runs off into lakes, creeks, rivers and streams.

Climate Central recently looked at the future inland flood threat. Their States at Risk report analyzed the frequency of high water runoff that could lead to flooding threats now and in the future. They came up with a Flooding Severity Index to quantify the runoff. The index is the average yearly sum of the daily total runoff which if more than the 95th percentile of a baseline from 1990 to 2010.Their index takes into consideration intensity of the runoff and the duration of the runoff in each state in the U.S.  OK, I know, that sounds like mumbo jumbo.  Here’s the bottom line…the research found that a large majority of states will face an increased threat of inland flooding by middle of the Century. This map shows the change in heavy runoff by 2050.  The blue shaded states highlight the states that have the increased threat.

Blog CC Inland flooding US

Of the 48 contiguous states analyzed, 42 face increased heavy runoff by 2050. The New England states have some of the largest projected increases in runoff. Climate Central’s findings were similar to the report from The National Climate Assessment. They found that in this area of the northeast that incidents of heavy precipitation have already increased 71% from 1958 to 2012.

In Tennessee, there is a smaller increase projected from 2000 to 2030.  There appears to be no increase from 2030 to 2050.

Blog CC Inland Flooding TN

One of the most important aspects of inland flooding is the number of people who live in harm’s way during these events.  Climate Central also researched the number of people already at risk by correlating the runoff data to the population living in the FEMA 100-year floodplain.  Florida and California, each have more than 1 million people at risk from inland flooding.

The power of water is truly amazing.

There is more water in the 7 day forecast.  I’ll have an update on the forecasts on Channel 4 News at 10pm.

Lisa Spencer

posted 9pm

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About Lisa Spencer

Lisa Spencer is the chief meteorologist at WSMV Channel 4 Nashville. You can catch her weathercasts weekdays at 5pm, 6pm and 10pm.
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2 Responses to Too Much Rain, No Where to Go

  1. Betty says:

    Were?

    Sent from my iPhone

    >

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