What caused the Upper Makefield fatal flash flood?
A flash flood in Upper Makefield took at least six lives as rapidly rising waters swept them away, damaged homes, wrecked roads, and took the community by tragic surprise.
On July 15, six inches of rain fell in just two hours. The water in Houghs Creek rose so quickly, overcoming its banks and spilling onto a nearby road.
A dozen people needed to be rescued as their cars were caught adrift. Within a day, crews had recovered the bodies of five victims; a sixth was found on Friday and one child is still to be recovered.
A vigil was held and citizens are concerned if the next flood could hit them. While they are worried about the next flood, they are also asking local and state to help them prepare if it does happen.
Did climate change have a role in the Upper Makefield flood?
Storms like the one in Upper Makefield are a common occurrence in summer, with August typically the wettest month of the year in Bucks County.
Jon Nese, associate head of undergraduate programs in the Department of Meteorology and Atmospheric Science at Penn State, said a moisture-rich atmosphere during summer months makes the area ripe for heavy rain storms.
“You have the warmth, the moisture, and that can help build tall clouds, which is essential for thunderstorms,” Nese said.
Amanda Lee, a National Weather Service meteorologist at Mount Holly, pointed out that on average, the yearly total amount of precipitation hasn’t changed much in the last 20 years. The 10-year average from 2003 to 2012 was 46.73 inches of rain per year, and the 10-year average from 2013 to 2022 was 47.22 inches — a statistically insignificant difference.
And while the overall amount of precipitation throughout hasn't changed, Nese said, there are more single storms with more precipitation occurring more frequently.
Recent research shows, he explained, that in recent decades a larger percent of the year's total amount of precipitation seems to come on one day where there is heavy rainfall.
Ness said the atmosphere is experiencing more conditions that “make certain events a little more likely.”
When the rains came: As community gathers for Upper Makefield flood vigil, organizers talk of miracles
What else contributed to the Upper Makefield flood?
This storm was “of a different nature," said Delaware Riverkeeper Maya K van Rossum.
According to Nese “It just rained too hard” dumping roughly 6 inches on Upper Makefield in a few short hours.
But sudden rains alone aren't to blame for the fatal flooding.
According to Michael Mann, professor of Earth and Environmental Science at the University of Pennsylvania, urban areas are more likely to see floods when paved and landscaped areas replace natural environments.
What happened at Houghs Creek was “a bit of bad luck,” Mann explained, considering the creek is designated as a “special flood hazard area” by FEMA.
He explained that “because of the topography and waterflow, it is considered to have a 1% chance of experiencing a flood in any given year." However, he explained that in general flooding has worsened due to “human-caused climate change” unaccounted for by FEMA.
“Inappropriate development practices and the failure to protect and preserve the natural landscapes in the Bucks County region, we have already been experiencing increasing human induced flooding,” van Rossum argued.
“In Bucks County we do have too many places and spaces where there is development that unnecessarily compromises the environment and its ability to soak up floodwaters. There's too much development in the floodplain,” van Rossum said. “There's a failure to protect critical buffer widths that protect the integrity of the creek, soak up floodwaters, give floodwaters a place to go when waters rise, but also makes sure that people are away from the waters edge, so when flood waters do rise they are not in the path of harm.”
More: How the Upper Makefield flooding happened: A timeline of tragedy
Will Bucks County see more flash flooding?
Mann said research suggests that the jet streams, or wind currents that affect weather patterns, are “slower, more wiggly.”
This ends up causing more persistent weather extremes. Both Nese and Mann also said that there is a direct relationship between an increase in temperature and the amount of moisture in the air, which intensifies with climate change.
“Human-caused warming, from fossil fuel burning primarily, means that the atmosphere is warmer than it used to be, and contains as a result more moisture. So, when you do get rainfall, you get more of it,” Mann said.
Which means events like the Upper Makefield flood may become more common in the future, Nese added, and not just in Bucks County.
More: Before the fatal floods took her life, Yuko Love was known for her kind, loving spirit
More: They spent more than 40 years together. The fatal flooding took their lives
More: South Carolina mom who died in Upper Makefield flooding was proud mama, sister, friend
More: Titusville resident killed in Upper Makefield flooding known to always lend a helping hand