Amid Widespread Drought In U.S, Some Nasty Flash Floods

Flooding in Burlington, Vermont in the summer of 
2017. It is dry so far this year, but early summer
seems to be a peak season for flash floods
in much of the eastern United States

Droughts and heat waves are dominating the nation's weather headlines of late, but there's quite the opposite problem happening in some parts of the country: Flash floods. 

This is arguably peak season for flash floods in much of the United States. The severe storms season of the spring evolves into, yes, occasional bouts of high winds and tornadoes, but also heavier rain.  

Being into at least climatological summer, the atmosphere is warmer. Warmer air can hold more water than cooler conditions. Given the right weather set up, the result is torrential downpours in spots.  June becomes a month particularly prone to flash floods. 

Climatologist Brian Brettschneider  (@Climatologist49 on Twitter) figured out that June 8 is the climatologically wettest day of the year in the contiguous United States, at least based on averaging out data from 1991-2020. 

Climate change has brought the potential for even heavier downpours than in the past. The air, especially in the eastern half of the nation, can get warmer and more humid than it could decades ago, at least in general. The result is heavier flash floods. 

The worst of the flooding this week was in southern Arkansas and northern Mississippi, especially on that notorious June 8.  In the past few days 12 to 18 inches of rain has soaked this area, leading to widespread flooding.

The problem was ongoing this morning.  A particularly dangerous situation was declared early today in northern Mississippi for torrential rains and flash flooding ongoing as I write this.

In the East, torrential thunderstorms in the soupy, hot airmass this past week has brought damaging flash floods from Downeast Maine all the way down the coast into the Carolinas.  More than five inches of rain fell in parts of eastern Maine early Wednesday. Up to seven inches of rain drowned some areas of Pennsylvania. 

It IS that time of year, as noted.

Some of the most notorious, deadly historic floods in U.S. history have hit different areas of the nation in past decades in the end of May and in June. 

The famous Johnstown Flood in Pennsylvania on May 31, 1889 killed 2,209 people.  It was caused by a dam, poorly built, collapsing amid torrential rains. 

Ten years later, a historic flood along the Brazos River in Texas killed 289 on June 17,1899. In 1903 yet another flash flood in the mountains around Heppner, Oregon killed 324 people.

A flash flood in and around Rapid City, South Dakota, caused by up to 15 inches of rain from a thunderstorm parked over the Black Hills, killed 238 people on June 9, 1972.  

That same month, early season Hurricane Agnes caused immense flooding in Pennsylvania, New York State, and other parts of the Mid-Atlantic.  That flood killed 117 people and caused $3.1 billion in damage. 

More recently, Ellicott City Maryland was wrecked in a dramatic flash flood on May 27, 2018.

You get the picture. 

Here in Vermont, we can still get flash floods even in dry years like this one. That is, if it rains hard enough in a short enough period of time.  Part of far southeastern Vermont was under a flash flood warning for a time Tuesday, but no reports of anything serious came from that.

Going forward, the forecast for Vermont continues to feature too little rain - not too much  rain- in the next week or so.

Still, there have been some serious flash flood episodes in Vermont during June.  One of the worst floods in Vermont history hit on June 30, 1973.  Destructive flash flooding hit Vermont in June, 1998 and to a slightly lesser extent in 2005, 2006, 2008 and 2013.