Meteorologists use statistical measures to rate rare storms. According to The Baltimore Sun, a “100-year flood means that there is one chance in 100 of a flood or storm in a year. A 500-year flood means there is a 0.2 percent chance.”

Not that these numbers guarantee that such storms will hit on schedule every 100 or 500 years. Two such floods could come in the same year. The Intergovernmental Panel on Climate Change is confident that climate change increases heavy rainfall in hurricanes and believes “human-induced climate change is likely the main driver” for the global rise in heavy rainfalls.

Fifty years ago in Occoquan

June 2022 marks the 50th anniversary of the devastation caused by a storm called Agnes. According to Earnie Porta, the mayor of Occoquan, Virginia, Agnes started out as a tropical depression over Mexico’s Yucatan Peninsula, and then became a tropical storm and finally a hurricane. When it hit Florida, it had weakened to a tropical depression.

But Agnes was just getting started. She was upgraded again to a tropical storm and became stronger over the Atlantic Ocean. At that point, she dumped tremendous amounts of rain on the mid-Atlantic region and flooded the Town of Occoquan, exceeding all 100-year storm predictions. Fourteen inches of rain fell in 24 hours, and residents saw boats and empty caskets floating down the street.

“The violent impact of the storm caught most by surprise,” writes Porta. “As the floodwaters surged, authorities evacuated the Town of Occoquan. At the town’s western end the one-lane iron Pratt truss bridge, which had stood for 94 years and carried Route 123 across the Occoquan River, was itself carried away by the floodwaters of Agnes. Homes and businesses were wiped out, never to return.”

Porta says that “the damage to Occoquan was a seminal event in the town’s 20th-century history.” The businesses that closed their doors after the flood were replaced by new ones, and the town now offers more than 100 art, antique and specialty stores and restaurants. Agnes was devastating to Occoquan, but it led to a transformation of the historic town.

History repeats itself

Close to fifty years after Agnes, a fictional storm hit Occoquan in my mystery novel Windows of the Heavens. After a night of heavy rain, water covered the streets and the town’s maintenance man, Tim Underwood, drove his truck slowly through the floodwaters. A pastor named Harley Camden looked down the wrought-iron steps of his townhouse and saw that the receding water was now only about half-way up the first step. He motioned for Tim to stop, and then climbed into the truck.

“What do you need, Harley?” asked Tim.

“Just a ride, Tim. I want to see what happened.”

“This is serious,” said Tim, shaking his head. “Worst I’ve seen since seventy-two. You really shouldn’t be outside.”

Harley felt a flush of shame. He knew he was being a voyeur, but at this point he wasn’t going to turn around. “Terrible,” he agreed. “What happened in seventy-two?”

“Hurricane Agnes. The rain from that storm caused the Occoquan River to overflow the dam. A steel bridge was completely swept away. And downtown Occoquan was completely flooded.”

“That’s awful,” said Harley. “Did anyone die?”

“No, thank God. But if the dam had broken, people would have. This is the worst since Agnes.” Tim put the truck in gear, and as he began to inch forward, he said, “Since you’re in the truck, you may as well come along.” As they crossed Union Street, Harley looked to the right at the delta in the gravel parking lot. Water was flowing through a trench cut through the middle of it, and several inches of thick mud and scattered debris covered the rest of the lot. The Occoquan River was still running high, with its water spilling into the first floors of shops along the bank. Hope they paid their flood insurance, thought Harley.

A town transformed

“What happened to the porch of the gift shop?” asked Tim, looking to the left.

“Washed away,” said Harley. “I watched it collapse and get swept way.”

“Unbelievable,” Tim said.

On the south side of Mill Street, the Riverview Bakery seemed to have escaped major damage, but the first floor of the brew pub on the north side, next to the river, was full of water. Overall, it appeared that the buildings on the river side had suffered the worst, but everyone had been hit. When Tim waved to the owner of a card shop and asked how he was doing, the man replied, “Flooded basement! Can’t even get down the stairs!”

Then they pulled up beside the firetruck at the corner of Ellicott and Mill, and saw a sight that put the rest of the town’s damage into perspective. At the end of Ellicott was a three-story brick apartment building that had been connected to a white clapboard candle shop. Above the candle shop was a single apartment in which the owner lived, and a narrow alley separated the shop from a row of old but well-maintained brick office buildings on the other side.

Now the brick apartment building stood at an odd and unexpected distance from the office buildings, looking like a row of teeth with one knocked out. The candle shop had been washed away.

Fifty years after Agnes, a devastating storm again hits Occoquan. The story is fiction, but the danger is a fact.

To order Windows of the Heavens, which is the sequel to my Occoquan-based murder mystery City of Peace, click here.