Agnes at 50: Here's a look back at the devastating storm by the numbers
Tropical Storm Agnes, which caused historic flooding 50 years ago this month, still ranks as the most destructive storm in central Pennsylvania.
Since Agnes, only Tropical Storm Lee in 2011 produced comparable rainfall amounts in central Pennsylvania, said Kyle Elliott, director of the Weather Information Center at Millersville University. More than 11.16 inches fell at the York Airport in Jackson Township, according to the National Weather Service.
In 1972, Agnes was the first named storm of the hurricane season. It made landfall in Florida as a Category 1 and was downgraded to a tropical depression. Agnes later regained strength to become a tropical storm and merged with another storm system as it hit the Northeast.
Central Pennsylvania already had experienced an abnormally wet spring when Agnes dumped torrential rain in mid-June, Elliott said.
"An already wet pattern preceding a historic rainfall event is a recipe for disaster since the ground will not be able to absorb much moisture," he wrote in an email.
The catastrophic flooding destroyed homes and shut down Harrisburg International Airport, railroads and roadways, according to a government website dedicated to the anniversary of the storm.
Downtown York was under water in parts of the city, causing about $10 million in damage. Many had to be evacuated because of the flooding.
Glen Rock was another community hit hard. Cars, tires, groceries and more floated away.
Tropical Storm Agnes, 50 years ago:‘It was like something out of the Bible’
Here's a look at the impact of Agnes, by the numbers:
$3.1 billion: The damage caused by Hurricane Agnes to the East Coast
128: Deaths caused by Hurricane Agnes.
50: The number of fatalities in Pennsylvania.
Agnes, 50 years ago:Storm left behind ‘mud, dead rats, old tires, and all kinds of trash’
4: People declared dead in York County.
12: The number of states, including Pennsylvania, affected by widespread flooding.
16 inches: The amount of rain that fell in York between June 20 and June 25.
13.5: Inches of rain that fell in York on June 22, 1972. The weather station’s observation center recorded about an inch the day before and an inch the day after.
10.27: Inches of rain that fell at Millersville University in Lancaster County.
1.1 million: Gallons of water per minute that spilled over Indian Rock Dam, flooding York.
$12,917,000: The damage caused in York. Much of it was to low-income housing, and some dwellings could not be restored.
30,000 cubic feet per second: The discharge unleashed on the Codorus Creek during the storm. The high was in August 1933, when the discharge was about 32,000 cubic feet per second.
10 feet: The reduction in the crest stage for the Codorus Creek, thanks to Indian Rock Dam.
1,080,000 cubic feet per second: The discharge on the Susquehanna River at Marietta, Lancaster County. It beat the previous record of 787,000 cubic feet per second, set in 1936.
32.5 feet: The crest of the Suquehanna River in Harrisburg. It surpassed the 1936 record of 29.2 feet.
17 feet: The flood stage for the Susquehanna River at Harrisburg.
64.5 feet: The crest of the Susquehanna River at Marietta. Flood stage is 49 feet.
18.33 feet: The crest of the Yellow Breeches Creek at Camp Hill. Flood stage is 7 feet. In 1975, the creek set its highest crest at 18.77 feet during Hurricane Eloise. The creek divides York and Cumberland counties.
Better communication, other changes since Agnes
Officials have learned a lot from Agnes, said Charles Ross, service hydrologist with the National Weather Service in State College.
Communiciation with the public has improved in 50 years, giving residents advanced early warnings and time to prepare to evacuate, if needed.
During Agnes, the weather service, which had an office in Harrisburg at that time, lost power and its ability to disseminate warnings. For hours, the agency could not let the public know what was expected to happen with the Susquehanna River.
The Williamsport office, which kept its power, was issuing warnings to the public. However, no one knew because the way information was disseminated back then was completely different than today, Ross said.
Today, the weather service has generators, and its sister offices in New York and Virginia can serve as backups, he said. Agencies practice together for emergencies.
"Things have improved a lot," Ross said. "But you know down the road in the next decade-plus, we're gonna even see better, you know, more sophisticated changes" in technology and communication.
Federal programs have helped people with properties in the floodplain. In some cases, buildings have been raised. In others, they have been bought out to reduce the number of structures in the floodway.
Residents, especially those who live in an area that floods, should watch the weather and know the level at which they need evacuate. They also need to be familiar with how to escape safely and have important items ready to take with them.
Even those who don't live near water should be familiar with roads that flood, he said. Drivers can come upon a road covered with water if emergency responders have not yet closed it.
"We want everybody to be prepared for the next Agnes because it could happen," he said.
Sources: National Weather Service, U.S. Army Corps of Engineers, the York Daily Record archives, and Kyle Elliott, director of the Weather Information Center at Millersville University.
Teresa Boeckel is the trending reporter for the York Daily Record, part of the USA TODAY NETWORK. Contact her at email@example.com, by phone at 717-771-2031 or on Twitter @teresaboeckel.