This story was produced through a partnership with Climate Central, a non-advocacy science and news group. Raina DeFonza, a researcher and writer with Climate Central, contributed reporting.
Michele Pattenaude battened down her home in the southern Maine coastal town of Biddeford a couple days before Christmas in 2022 as she prepared for a forecasted heavy rain and wind storm.
Carnage greeted her the next morning when she walked downstairs to the living room. The storm, with hurricane-force winds and storm surge accompanied by an astronomical high tide, had pushed into her home by the beach through what she suspected were poorly installed patio doors.
“Water was just rushing through the living room, dripping downstairs and pouring through a light fixture in the basement,” she said. “When I soaked it up, it was obvious it was coming from underneath the patio doors.”
The damage led to a mold outbreak so severe that the basement had to be sealed off. Pattenaude’s experience highlights how increasingly severe storms in Maine can present more than a flood risk. The resulting wet basements and attics create ripe conditions for mold to grow, a situation enhanced by humidity and warming temperature trends, with last summer’s temperatures rising toward historic highs.
As fossil fuel pollution traps heat, it is intensifying rainfall and raising seas, bringing more inland flooding, damaging homes and contributing to mold. When it rains, it rains more. The intensity of rainfall per hour in Portland has increased 15 percent since 1970, according to Climate Central.
Indoor molds can release toxic particles that trigger and exacerbate asthma attacks, worsen allergies and spur a host of respiratory issues including shortness of breath, wheezing and coughing. Drying and cleaning moldy homes can cost thousands of dollars, on top of costs to replace water-soaked walls, fix damaged roofs or rebuild decks.
“Anything that is wet or becomes water damaged, if left unattended, is going to grow mold,” Jason Feugill, president of Dry Masters of Maine, said. “Last year was very challenging with the rate of mold growth due to weather patterns of high humidity and rain.”
The growing frequency of flooding is “very noticeable,” and “the ground is so saturated it is forcing water into basements, sometimes for the first time,” said Jon Symonds, senior production manager at Servpro in Hermon.
The National Weather Service offices in Gray and Caribou issued more flash flood declarations from January to October 2023 than any other year in the past decade. There were 49 flash flood warnings issued statewide in that timespan, up from the previous high of 34 in 2013.
The southern part of the state saw more warnings than in the north, where the storms were not as severe, said Louise Fode, warning coordination meteorologist at the National Weather Service in Caribou.
Preliminary damage estimates for four of the worst storms in 2023 totaled more than $15 million, according to the Maine Emergency Management Agency. That figure only includes a few major damage sites and restoring the sites only to pre-existing storm condition. Those four were Winter Storm Elliott in January, the May Day storm, the Franklin County flash flood in June and the Oxford County flash flood, also in June. The Maine Emergency Management Agency expects the total damage costs to be higher.
“Flash flooding really was the story of 2023,” said Sarah Jamison, senior hydrologist with the National Weather Service Forecast Office in Gray.
That was especially true in Maine’s rivers, which typically don’t overflow as much as they did last year, she said. In June 2023, the Oxford County town of Andover and the Franklin County town of Jay saw rainfall amounts of about six inches over several hours that damaged roads.
“That’s not the kind of rainfall we’re used to seeing, and our infrastructure in many cases was overwhelmed,” Jamison said.
Twin flooding storms on Jan. 10 and Jan. 13 compounded difficulties for homeowners facing cleanups. The third significant wind and rain storm of 2024 on March 10 prompted power outages, further stressing residents trying to recover from the January storms, which already had caused an estimated $70.3 million in damage to Maine’s public infrastructure alone.
For some homeowners and businesses, the unsparing storms brought flooding for the first time.
The Maine Emergency Management Agency said about 40 of the complaints it received by the end of February included worries about existing or possible mold. The most complaints, 21, came from hard-hit York County, where one homeowner lamented that they lost power, so their sump pump wouldn’t work, and the four feet of water in their basement caused visible mold. Remediation was not covered in their insurance policy, which is not unusual for storm flooding in Maine.
Even in Gardiner, which experiences regular flooding from the Kennebec River, some residents were not prepared for the water that got into their homes, with a few people asking the fire department to dry out their basement because they didn’t have a sump pump, city Code Enforcement Officer Kris McNeill said.
“We have had some discussion about how to help people in the future and possibly write an ordinance that requires properties damaged by flood to be emptied out and their basements dried out immediately,” McNeill said. “But that’s just in early discussions.”
The Maine Public Health Association is focusing on education around mold exposure, Associate Director Matt Wellington said. He questioned whether Maine residents fully understand that mold can affect their respiratory levels and have other health consequences.
“So they might leave a shingle off their roof after one of these extreme weather events because they just don’t want to deal with that cost, or it’s a headache,” he said. “Then mold grows in the house and gets worse and leads to more severe impacts.”
Maine has some of the oldest housing stock in the nation, but older homes generally have enough ventilation to help stave off mold, Ben Barringer, owner of remediation company Rainbow International Restoration in Scarborough, said. At greater risk are newer homes that may have been built with tight windows and dense insulation to keep energy inside for efficiency. Mold spores can be spread through the air, on clothing and on pets.
“We’re finding a lot of the homes that are built really tight are having huge issues, mainly because they are not ventilated properly,” he said. “Moisture is getting trapped in people’s homes, and it’s just sitting there, stagnant.”
Barringer said even a small space can be costly to rid of water damage and mold. A small closet can run $1,000, and a whole house can be $50,000 to $70,000, he said. Cleaning up mold typically is not covered by insurance unless the damage is caused by a sudden, accidental loss such as a tree falling on a roof and creating a leak, he said.
Flooding isn’t always needed to cause mold to flourish in Maine, where humid air is getting even damper, said Christine Crocker, executive director of the Maine Indoor Air Quality Council, an advocacy nonprofit. Last summer was the second wettest on average across Maine.
Warmer air can hold more moisture, so humidity has increased along with rising temperatures. Since 1950, Maine summers have seen an average increase of 4 to 6 degrees Fahrenheit in equivalent temperature, a metric that considers both heat and humidity, according to Climate Central.
“Our air in the summertime is like Orlando,” Crocker said. “Think about your iced tea glass, you know, your hand gets soaking wet because it’s cold inside the glass and warm and moist on the outside. So condensation forms. And that definitely happens in the basement.”
That is why it is important to assure the home has adequate ventilation and drainage. If moisture is an issue, using a sump pump and dehumidifying the area are crucial.
“Dehumidifiers are really essential when you’re dealing with high humidity situations,” Symonds of Servpro said. “You probably won’t have to run them in the winter but definitely will in the summer.”
There’s also a human toll with water and mold damage, said Barbara Rapoza, a spokesperson for Servpro. Apart from the stress of several days of cleanup, flood victims have lost personal items that are dear to them.
“It’s so overwhelming, and people are in panic mode because the water is coming in so quickly,” Rapoza said. “We can only get there once the water has stopped.”
More information on dealing with mold is available from the Maine Indoor Air Quality Council, “All about mold,” and the Federal Emergency Management Agency, “Prevent mold from becoming a secondary disaster.”
Lori Valigra is an investigative environment reporter for the BDN’s Maine Focus team. She may be reached at [email protected]. Support for this reporting is provided by the Unity Foundation and donations by BDN readers.
