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A Devastating World Record Pennsylvania Rainfall In July Of 1942

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At the current time, many people are attempting to recover from historic flooding that has crippled parts of the Midwest and Northern Plains of the U.S.  I’ll now take you back eighty-two years to July 1942 when nearly three feet of rain flooded rivers, compromised dikes, and dams, and submerged parts of northern Pennsylvania!

In the area around Smethport and Port Allegany, Pennsylvania, the skies darkened on July 18, 1942.  Rain had already fallen the night before but the next few hours would be “hell on earth” as described by one area resident. The rain began to fall, it suddenly became relentless and unforgiving. Lightning darted across the sky among the clouds. In less than 5 hours, a world-record rainfall had inundated the area, lives were lost and many became homeless.

The Event

Around 8:30 p.m. on Friday, July 17, 1942 rain began to pour down furiously near Cohocton, New York. Heavy rain and thunderstorms continued and thunderstorms sagged southward into Pennsylvania.

The rain became extremely heavy around Smethport and Port Allegany, on Saturday, July 18th. The most intense rain fell in 5 hours. Residents indicated that the electrical storm was the worst they had ever witnessed. Lightning was constant across the sky, but it danced from cloud to cloud rather than cloud to ground.  As floodwaters continued to rise, and the relentless rain continued, many thought that they would drown.

Residents recalled that the rain wasn’t just falling in drops, but more like streams. Here are some accounts from one area in Pennsylvania.

In the Austin, Pennsylvania, region, residents said the rain did not come down in drops. They had the visual impression, at least, that the rain came down in streams which they likened to strings and ropes… some people had not been able to reach shelter and were afraid they would drown during the downpour through lack of oxygen. One man expressed the effect by saying it was like breaking water after a long dive, with lungs bursting, and water pouring down his head.

The dam at the Williamson Pulp and Paper Company at Austin was breached which hastened flooding of the town as you can see in the photo below (from a USGS report).

 

Photo showing floodwaters after a dam break at Austin, Pennsylvania on July 18, 1942. Photo Credit-USGS.

There were reports of massive quantities of gravel and rock being washed down small gullies and deposited as alluvial fans at the mouths and reports of bedrock being ripped out and carried downstream as the relentless rain continued.

There were numerous reports of debris flow or “blowouts”, where all overburden above the rock became fluid and flowed down steep hillsides.

One debris flow swept from the top of a hill to its bottom in Kettle Creek, a distance of more than a mile. The flow was narrow at the top and roughly a quarter-mile wide at the bottom. Some slides moved for hundreds of feet with trees upright, and some of the trees were later found to continue growing in the new location “as though nothing had happened”.

In Emporium, Pennsylvania, an incredible amount of rain fell in a short period. The estimated rainfall rate was over TEN inches per hour.  There was massive flooding over a short time. The dikes at Emporium were breached and most businesses suffered extreme damage. Below are photos from Emporium taken 1 hour apart. (USGS/Ginny’s Geneology Page).

There were many accounts of an “almost instantaneous rise” in the water from 5 to 8 or 10 feet. Buildings in Austin were being knocked off their foundations and the water was 4 to 5 feet deep on the main street.

The heaviest rain fell between Smethport and Port Allegany, Pennsylvania. Some locations received a whopping 34.50 inches of rain from the event. A rainfall total of 30.7 inches in a 4 1/2 hour period set a world record around Smethport where extreme flood damage was reported.

Storm Impacts

Here is an account of the storm from a USGS publication :

On July 18, 1942, north-central Pennsylvania and adjacent areas in New York were visited by destructive floods of unprecedented magnitude. The principal areas affected were Elk, Cameron, McKean, and Potter Counties in Pennsylvania, and Cattaraugus, Allegany, and Steuben Counties in New York.

Rainfall of more than 30 inches was reported in several localities, and on about 200 square miles the rainfall was as much as 20 inches. The rainfall was greater than 10 inches on more than 2,000 square miles!

The resulting floods produced the highest crest stages on record! First Fork and Driftwood Branch of Sinnemahoning Creek and on upper Allegheny and Clarion Rivers. Flood discharges on small drainage areas less than 100 square miles were as great relative to the drainage area recorded on streams in Pennsylvania and adjacent areas in New York.

Practically all the towns along the streams were inundated to a damaging extent. The dikes at Emporium, Pennsylvania, were overtopped and about 60 percent of the town was flooded; the water was 5 feet deep in the middle of Broad Street Square. At Austin, Pennsylvania, the event was reminiscent of the historic flood disaster of September 30, 1911, when the dam broke and 80 people were killed.

A photo showing houses knocked off their foundations due to floodwaters at Austin, Pennsylvania on July 18, 1942. (USGS).

The dam of the Williamson Pulp & Paper Co.’s reservoir with a capacity of 65,000,000 gallons at spillway crest was breached, pouring floodwaters upon the town of Austin; buildings were knocked off their foundations and water was 4 to 5 feet deep on the main street. Many residents of the area were rendered homeless by the event.

Port Allegany probably suffered the greatest damage per capita of any town in the area. Virtually every business building was flooded with 3 to 20 feet of water. Over 150 people attending a conference in the Free Methodist Church were rescued from treetops, roofs, and floating wreckage. The church was washed against a nearby silk mill; it caught fire with buildings and other adjacent structures destroyed.

A photo showing the Bridge of Coudersport & Port Allegany R. R. damaged by flood waters (USGS).

Above Johnsonburg, Pennsylvania, a dam broke, and a wall of water 8 feet high was reported as having swept through the town. Eighteen families had to be rescued with makeshift rafts, and houses were moved off their foundations and pushed together All these communities supported industries that suffered heavily, at a time when capacity production was needed for the war effort.

Public utilities and transportation systems were badly damaged. Water, gas, and electric services were disrupted in many communities. Railroads, highways, and bridges were washed out.

The collapse of a bridge near Ridgway marooned a passenger train. It was estimated that 75 miles of Pennsylvania Railroad track were damaged. The Coudersport and Port Allegany Railroad between Roulette and Port Allegany and the Baltimore & Ohio Railroad between Sinnemahoning and Austin were so badly damaged that they were abandoned. Overall the 27 miles of the Baltimore & Ohio Railroad suffered extreme damage.

The situation could have been much worse. Three separate drainage basins were involved with the storm the Susquehanna, flowing into the Chesapeake Bay, the Allegheny, the headwaters of the Ohio River; and the Genesee, a tributary to the Saint Lawrence River. Rainfall distribution over three basins explains the lesser severity of flooding on the main stems of these rivers, compared to the headwater streams and runs of each basin.

All told, 15 people lost their lives during the event and damage estimates were around 10 million dollars (around 193 million in 2024 dollars)!

Meteorological Assessment

The U.S.Weather Bureau and the United States Geological Survey assessed the storm.  Below is a rainfall map of the impacted area showing more than 35 inches at Port Allegany, Pennsylvania.

In 2009, a more detailed assessment was produced in 2009 by Ed Tomlinson, Ph.D. and Bill Kappell (Applied Weather Associates), and Dwight D. Hoare, P.E. St. Marys, PA (Water Authority. Here are their findings – applied weather associates.com

This assessment was presented at the Northeast ASDSO Conference at State College, Pennsylvania (June 14-16).

 

Below is the surface weather map for Friday, July 17, 1942. A stationary frontal boundary was draped over the Great Lakes and extended into New York. With a static boundary like that, the upper-level winds were probably light so any storms would be slow-moving. There was ample moisture (high dewpoints).

A surface weather map from July 17, 1942, shows a stationary frontal boundary over the eastern Great Lakes (heaviest rainfall area circled). Map Credit- NOAA Central Library. 

Hopefully, this area won’t see anything like this again!

 

 

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