More than 5 inches of rain fell in roughly three hours on Sunday morning, Sept. 13, in parts of North Jersey, flooding streets and prompting water rescues. NJ 101.5 reported that both the National Weather Service and Rutgers University's New Jersey Weather Network measured more than 5 inches in Harrington Park, Paramus, North Caldwell, North Haledon and West Caldwell, with most of it falling between about 7 and 10 a.m.

In Paterson, Mayor Andre Sayegh said emergency crews rescued about 20 people, including a woman who fell out of her wheelchair and ended up floating in the street, NBC New York reported. He said there were no immediate reports of deaths or severe injuries. The Weather Channel reported that dozens of Teslas were swamped at a dealership in Totowa.

State Climatologist John Krasting of Rutgers said preliminary estimates show the rain was "at least a once-in-a-generation event in towns such as North Haledon, Haworth, and Little Falls."

A Saturated Atmosphere Met a Stalled Front

Krasting explained that the atmosphere was saturated with moisture. A stalled front and a slow-moving area of low pressure then kept the rain falling over the same communities.

Parts of the tri-state area saw rainfall rates of 1 to 2 inches an hour, NBC New York reported. The storm was also highly localized. Central Park recorded only about half an inch by late morning, while totals near 4 inches had already been reported in parts of Paramus, Paterson and Wayne. The Rutgers network estimated how rare the rain was at its North Haledon station using NOAA's Atlas 14 precipitation climatology.

Once-in-a-generation language describes how rare the rain was based on historical records. It is not a guarantee about how long it will be until the next event. Warmer air can hold more moisture, which can make heavy downpours more intense, but Sunday's storm has not been formally analyzed for any climate link.

Passaic and Bergen Counties Hit Again

Krasting said parts of Passaic and Bergen counties "took it on the chin, once again." New Jersey received more than 50% above its average August precipitation, according to NOAA's national climate report, a wet stretch that preceded Sunday's storm.

One event drew particular scrutiny. The Racefaster Half Marathon went ahead under a Flash Flood Warning, with parts of the course in Saddle River County Park under waist-deep water. The start in Ridgewood had already been delayed two hours, and NBC New York reported that 250 people finished. NBC New York later reported that Bergen County is investigating the race video.

As the skies cleared, Paterson's annual Dominican parade stepped off Sunday afternoon after a slight delay. The flooding reached well beyond New Jersey. In Westport, Connecticut, emergency responders conducted 13 rescues of people trapped in vehicles, and the coast from Norwalk to Westport received 6 to 7 inches of rain. Metro-North and Amtrak service on the New Haven Line was suspended, Connecticut Gov. Ned Lamont announced.

Hidden Hazards After the Water Recedes

The danger does not end when the rain stops. NJ 101.5 Chief Meteorologist Dan Zarrow warned that floodwater almost always contains sewage and bacteria, and that waterways often do not crest until several hours or even days after heavy rain ends.

The greatest burden falls on residents of low-lying streets and basement apartments, drivers caught on flooded roads and people with limited mobility. Owners of flood-damaged vehicles, including electric vehicles, should contact their insurer and dealer before trying to drive them. Standard homeowners policies generally do not cover flood damage, while comprehensive auto coverage typically does, so checking policy details now can prevent surprises.

Households cleaning up should photograph all damage before removing anything and dry out wet areas quickly to limit mold. Anyone who touched floodwater should wash thoroughly, and anyone with an exposed wound should watch it for signs of infection.

Warning Signs and Next Steps

Flash floods rise quickly, and it does not take much moving water to sweep a person or a car away. Westport's fire department urged residents to avoid flooded roads and to "never drive around barricades." Water crossing a roadway or a sudden rise in a nearby stream are signs to move to higher ground immediately and call 911 if trapped.

Residents can sign up for their county's emergency alerts and follow the National Weather Service office in New York, which covers North Jersey. The Rutgers weather network publishes local rainfall data.

Next steps will come through local damage assessments. Sunday's rain was extreme, fast, and concentrated over communities that have flooded before. Residents in flood-prone neighborhoods should plan now for the next storm and treat every flooded road as closed.

What Readers Want to Know

How much rain fell in North Jersey? More than 5 inches in about three hours Sunday morning in Harrington Park, Paramus, North Caldwell, North Haledon and West Caldwell.

Why was the rain so intense? Rutgers' state climatologist cited a saturated atmosphere, a stalled front and a slow-moving low-pressure system.

How many people were rescued? Paterson's mayor said crews rescued about 20 people. Westport, Connecticut, reported 13 rescues from vehicles.

Is flood damage covered by homeowners insurance? Usually not. Standard homeowners policies generally exclude flood damage, while comprehensive auto coverage typically covers flooded cars.

Can rivers still rise after the rain stops? Yes. Waterways can crest hours or days later, so residents should keep monitoring local forecasts.