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Tori Bauver was sitting at home on July 11 when the sky outside of the Wyndon Apartments in Wynnewood began to darken. Bauver watched the clouds roll in, then the rain come, blowing “literally sideways” outside her window. She remembers leaning in to see the darkening landscape and noticing that rain had begun to penetrate her windows. Then the “outside went stark white” and water started pooling on her windowsills.

“I was like, ‘Oh, my God. This is gonna flood. This apartment’s gonna flood,’” she said.

The light fixture above Bauver’s bed filled with water, then poured over the edges. The ceilings began to leak, then one by one, they collapsed. The building’s roof ripped off, and Bauver had a clear, and unsettling, view of the sky from her living room.

Bauver, now a resident of West Chester, where she and her partner moved after breaking the lease on her Wynnewood apartment, had been living in the Wyndon Apartments for two years when the July microburst storm tore through Lower Merion, destroying her home and more than $5,000 of her and her partner’s belongings. She was one of dozens of suburban residents who emerged from the storm with damaged property and a devastated home.

As the Philadelphia region sees hotter and more humid summers, flash flooding, extreme precipitation, and life-threatening storms have become a more common feature of daily life. Weather events marked by downed trees, dangerous flash floods, waterlogged roadways, and eroded bridges are, more and more, forcing suburban residents and cash-strapped local governments to pour millions into repair and resilience projects, all while large swaths of the region’s infrastructure are built to withstand weather patterns of a bygone era, one in which storms like July’s microburst happened once in a decade, rather than multiple times a summer.

As the region’s weather patterns intensify, officials and climate experts say the municipal mosaic of Philadelphia’s suburbs faces unique challenges when it comes to planning for a future marked by climate change.

The Philadelphia region’s changing weather

The average July temperature in Philadelphia has risen 4.4 degrees since 1940. In the 1900s, Philadelphia averaged four days per year with temperatures above 95 degrees, according to a 2024 EPA report. This summer, Philly has seen six days with high temperatures above 95 degrees, according to the National Weather Service. By the end of the 21st century, that number could climb to more than 50 days per year.

Hotter weather means more precipitation, and more frequent and intense rain events. For every 1.8 degrees the air temperature increases, the amount of water the atmosphere can hold increases by 7%.

“The infrastructure we have now is not always built to a standard to accommodate the extreme weather we’re seeing now,” said Chris Linn, manager of the Office of Resilience and Environment at the Delaware Valley Regional Planning Commission.

As Ray Courtney, a Lower Merion commissioner and chair of the township’s sustainability committee, said, “We get a 100-year storm every year.”

Flooding as ‘the biggest and most common hazard’

The impacts of intense storms are multitudinous and cascading, and the topography of Philadelphia’s suburbs can make it particularly difficult to find effective solutions.

Linn said flooding is “the biggest and most common hazard that communities face,” and it presents the most “consistent and pervasive” issues for municipal leaders.

Intense precipitation and flash floods, which have been a constant this summer, can disrupt transit, turn roads into rivers, and endanger residents’ lives. High winds and saturated soil frequently bring down trees, damaging homes and cars and knocking out overhead power lines. Disruptions to power can be particularly dangerous when residents are left without fans or air-conditioning during hot summers.

“I see roads flooding consistently, trees coming down, power going out, and then our local government spending resources every time one of these storms happens. It’s overtime costs and tree costs, and then also all the private citizens having to spend costs cleaning up trees and other debris,” Courtney said.

“These unlikely, freak events are really the ones that break us,” said Matthijs Bouw, architect and professor at the University of Pennsylvania’s Stuart Weitzman School of Design.

A key tool for managing extreme weather is stormwater systems, or the collection of drains, basins, ditches, and pipes that collect rainwater and snowmelt and move it from developed areas into local waterways. Stormwater systems are critical in moving water off impervious, or impenetrable, surfaces, like the parking lots, paved roads, and shopping centers often found in the suburbs.

The more developed a suburb is, the more runoff a storm will produce, increasing flooding risks, said Franco Montalto, professor of civil, architectural, and environmental engineering at Drexel University.

Yet many municipalities are contending with aging stormwater systems that require costly repairs. Lower Merion’s 2018 Comprehensive Stormwater Management Plan listed aging pipes, undersized infrastructure, operational costs, and increasing flooding as challenges for the township. Many of Philadelphia’s suburban communities are composed of buildings that predate a 1978 state law requiring counties and local governments to plan with stormwater management in mind.

Some communities are more vulnerable to climate impacts than others, with density, land cover, wealth, and the state of repair of existing infrastructure as factors. A 2021 climate change vulnerability analysis by Montgomery County found denser, water-proximate communities like Norristown and Pottstown to have some of the highest risk of increased stresses due to climate change. Greener, more rural parts of the county like New Hanover and Marlborough Townships presented lower risks.

How can communities mitigate impacts?

Experts described a range of interventions for managing climate impacts, from constructing rain gardens to rewriting zoning ordinances.

Maintaining a healthy tree canopy and building rain gardens can help rainwater permeate into the ground. Larger infrastructure efforts like stream restoration projects and floodplain maintenance can help stabilize the built environment.

However, Linn said, these interventions “don’t necessarily address more severe or catastrophic flooding in terms of mitigating those impacts.”

Long-term climate resilience, experts said, relies on making land-use and zoning decisions that preserve floodplains and natural drainage patterns and ensure stormwater systems can manage our new, rainy reality.

Montalto is interested communities that have become “safe to flood,” or that have created parks, parking lots, road medians, and other open spaces that trap water during floods, then properly drain it, keeping it away from buildings and roads. A basketball court built below a park, for example, can fill with water during a storm and slowly drain, mitigating runoff (one was recently installed in New York City). Copenhagen’s Cloudburst Management Plan, adopted in 2012 after a major storm, is a blueprint of sorts in Montalto’s mind.

However, bringing “safe to flood” infrastructure to Philly’s suburbs may be a far-out goal.

In the vast suburbs, the collection of boroughs, townships, and county lines makes unified action difficult, and forces officials to think along municipal, not watershed, lines. On the Main Line alone, rainfall and snowmelt drain into a collection of dozens of creeks and streams that do not start or stop where a municipal boundary is drawn, making it difficult to take coordinated and effective action when it comes to flood mitigation along certain waterways.

Finding the funding to repair and replace stormwater infrastructure, too, can be taxing, as local governments stare down costly projects, even with the availability of state and federal grants. Political will factors in, with municipalities differing in their desire and ability to use taxpayer dollars to tackle climate issues.

Philly’s suburbs, like the city, are also often old, dense, and built out, making it hard to retrofit them to be more climate-sensitive.

“So many of our communities are built out and have been built out for a long time, so the vulnerabilities and the challenges are built in to the community,” Linn said.

Solving ‘complex issues’ in Montgomery County

Despite the challenges, progress is being made, said Montgomery County Commissioner Jamila Winder.

Montgomery County in 2025 led a flood mitigation planning study for the 362-square-mile Perkiomen Creek Watershed, which stretches across Montgomery, Bucks, Berks, and Lehigh Counties. The study identified flood-prone areas, evaluated mitigation tactics, and worked to build a framework for long-term resilience. The county is currently in the process of carrying out a floodplain restoration project along the Wissahickon Creek in Whitemarsh Township. Both projects came to fruition after Hurricane Ida tore through the region, bringing record floods and killing multiple people.

The county has repaired 30 structurally deficient bridges since 2017 and has repaved dozens of miles of road. County workers also removed 200 dangerous trees earlier this year, resulting in a significant drop in emergency phone calls about tree damage, Winder said.

Lower Merion in 2021 hired its first full-time sustainability manager and in 2023 completed its first sustainability plan. Radnor Township has adopted a comprehensive climate plan, and Haverford Township has set out to achieve 100% zero-carbon renewable power by 2035.

The Pennsylvania Department of Environmental Protection in January announced more than $17 million in funding for environmental projects across the state, including stream restoration and stormwater management.

Winder said, “We’re seeing that when we work across federal, state, county, and local leadership, that we can come together to solve some of these complex issues.”

This suburban content is produced with support from the Leslie Miller and Richard Worley Foundation and The Lenfest Institute for Journalism. Editorial content is created independently of the project donors. Gifts to support The Inquirer’s high-impact journalism can be made at inquirer.com/donate. A list of Lenfest Institute donors can be found at lenfestinstitute.org/supporters.