Understanding flooding in all its forms

We've come to the end of July, and I think it's safe to say that we've dealt with more than our fair share of flooding in the Tri-State this summer. From mid-June through the month of July, numerous flash floods inundated roadways and invaded basements from Long Island to the Hudson Valley and many neighborhoods in between. We've also seen flooding on creeks and streams, and in mid-July, even the Connecticut River overflowed its banks. All of these events have one thing in common- too much water. But flooding manifests in plenty of different ways, requiring very different actions to prepare and protect. Let's break them down. 

Flash flooding, as the name implies, happens very quickly and usually impacts a small geographical area, like a few city blocks or a small creek. Flash Flood Warnings are issued when the threat is imminent or when the flooding has already started to happen. Since flash floods happen quickly, drivers are sometimes caught unaware or unprepared for the deluge, leading them to get stuck, like the driver below. 

But when a Flood Warning is issued, the flood potential is likely to last much longer. And, you can literally see it coming; when the word "flash" is not attached to the warning, we're talking about a type of flooding that creeps up more slowly, usually over a period of hours. Flood Warnings are most commonly issued for waterways such as rivers and creeks, because stormwater from nearby streets filters into these bodies of water over the course of hours or days, often long after the rain has stopped falling. 

And then there's coastal flooding, which can happen for a number of reasons. Storm surge is the most common source of major coastal flooding in the Tri-State. It can come from a storm like a Nor'Easter, like the record-breaking blizzard in 2016, or a tropical storm like Sandy in 2012. This aerial view of Mantoloking from the National Weather Service shows just how devastating coastal flooding can be.

High tide sometimes causes minor coastal flooding in the NYC area, especially during the New Moon and Full Moon phases. In fact, this type of flooding is possible tonight at high tide. 

As discussed back in my May 1st blog post, flooding events, especially flash flooding, are likely to happen more often in our warming world. In the city and surrounding area, we also have a lot of impervious surfaces, exacerbating runoff and making flooding even more common. As July comes to a close, it might surprise you to learn that Central Park's precipitation total is less than an inch above the monthly average, with 5.34" to date, and not nearly enough to break a record.

 It doesn't take a historic amount of rain to cause major problems in the Tri-State. With summer downpours getting heavier, it's important to be prepared for the potential for flooding, even on a "normal" summer day. NOAA provides tips for flood awareness and safety on the National Weather Service's website. 

Heat records and home runs have more in common than you might think

Meteorologists and climate scientists are always striving to improve their forecasting skills, but another skill many of us work on constantly is our ability to communicate the complicated science of the atmosphere to a general audience. Wait a second, you didn't realize that atmospheric science is complicated? Well, in order to qualify for the 400-level meteorology classes at Penn State, I had to take a class called "Ordinary and Partial Differential Equations", which is sort of like calculus multiplied by algebra. Most of the equations describing motions of the atmosphere are differential equations; below is one of the most fundamental of these, called the hydrostatic equation:

Trust me, I am fortunate to have survived that meteorology curriculum! And I am just one of many atmospheric scientists who are passionate about informing and educating the public. And that's why I'd like to share my favorite analogy to describe the difference between weather and climate. It requires a basic understanding of baseball, so if that sounds appealing to you, read on! 

Photo of Fenway Park taken by me

Baseball lends itself to a terrific analogy for the difference between weather and climate. Let's say your team has a superstar slugger like Aaron Judge, who hit the most home runs last year in MLB (and some would argue that he holds the record for the most home runs of all time; more on that later). Weather is similar to Judge's performance at the plate on any given day, with its ups and downs. Even a reliable hitter like Aaron Judge finds himself in a slump from time to time, as he did during the ALDS last October. Weather, similarly, doesn't always give you what you expect at a certain time of year. For example: 4th of July weekend of 2021, when  showers and a high temperature of only 66° ruined many a Saturday picnic. Or back in 2015, when we had a record-warm Christmas Day with a high temperature of - you guessed it- 66°. 

Climate, however, is akin to a player's career batting average, which is a long-term record of their performance. If I'm Yankees manager Aaron Boone, I don't know whether Judge will hit a grand slam in a game, but I know where he belongs in my lineup! Similarly, climate describes the long-term average conditions for a certain time and place. As the saying goes, "Climate is what you expect; weather is what you get". In the holiday weather examples above, we would have expected 4th of July weekend weather in the 80s and maybe a passing storm, not 60s and a washout. And for Christmas, temperatures in the upper 30s to low 40s are much more typical. 

This baseball analogy extends to our climate's warming, too. Remember earlier, when I mentioned that many people would argue that Aaron Judge holds the all-time home run record? That's because the official record was set during an era when performance enhancing drugs were commonly used in the sport. The carbon dioxide and other greenhouse gases that have been added to the atmosphere since the start of the Industrial Revolution are like the PED era of Major League Baseball. We can use professed steroid user Jose Canseco as an example. In the late 80s and early 90s, Canseco hit a LOT of home runs, but we can't point to any one baseball that ended up in the stands and say, "that one would have stayed in the ballpark if it weren't for the juice". 

Climate Central's Climate Shift Index and analysis of ongoing heat wave in 

Mexico and the American Southwest

So it is with global warming as well. A single record-breaking event cannot be directly blamed on greenhouse gases. However, a field called attribution science is adding statistical probabilities to many events, such as the continued triple-digit heat in Texas, which a Climate Central analysis shows was made 5 times more likely due to global warming. You can read much more about attribution science and Climate Central's methodology here. 

One last thing. Go Phillies!