A warming climate increases the likelihood of high intensity rainfall events. Here's how it impacts Pittsburgh.
The earth continues to warm at an alarming rate. The World Meteorological Organization confirmed that 2024 was the warmest year ever recorded based on six international datasets. Out of the many consequences of a warming climate, one major concern is the increasing frequency of high intensity rain events.
Researchers at Climate Central say the change in hourly rainfall rates in Pittsburgh has increased 28% since 1970. Pittsburgh is number 11 out of 12 on a list of larger cities that have seen the greatest increase in rainfall intensity rates between 1970-2024.
How does a warmer climate contribute to higher intensity rain events?
KDKA-TV First Alert Meteorologist Trey Fulbright met with Chris Gloninger, a meteorologist and the senior scientist at the Woods Hole Group, based south of Boston. Gloninger says the main idea behind a warmer atmosphere and heavier rain stems from the Clausius Clapeyron equation.
"Essentially, for every 1 degree of warming, Fahrenheit, that you see, the atmosphere holds 4% more moisture. What you see is heavier rainfall rates — more rainfall falling inside that one thunderstorm, a coastal storm, or a hurricane like a Harvey or a Florence that holds a lot more water and breaks all kinds of rainfall records."
Pittsburgh's terrain, soil type make rain events more dangerous
Gloninger says places like Pittsburgh don't have incredibly porous soil, which doesn't allow for efficient absorption of rainfall. The pitch and angle of the region's terrain also enables it to run off faster.
Not only is soil type and terrain a risk factor, but Pittsburgh's aging infrastructure adds to the risk as well. Gloninger says the area's aging stormwater systems are being overwhelmed by extreme rain events and that they are not designed for the recent rainfall rates.
How to protect your home from heavy rainfalls
There are some measures people and business owners can take to protect themselves. First, make sure your home or business is covered by flood insurance. Second, remove debris from drainage areas. Third, consider raising utility equipment in your home or business that could be damaged by flooding. Finally, watershed restoration and green development may be necessary measures used to combat flooding risks in the future.
