Picture this scenario. You check the weather forecast: “Chance of thunderstorms,” it says. You rationalize that the National Weather Service and other weather services include this phrase in many summertime forecasts. Some say it’s a matter of the weather services covering their rears just in case they pop up, even when the likelihood might be just 10-20%.

So, you and the family set off for a barbecue celebration. You’re driving along a two-lane road not that far from home, when, suddenly and without warning, the sky turns black, and a torrential rainstorm drops a large amount of rain on your vehicle and on the road on which you are traveling.

You slow down to a crawl as you try to assess the situation. “Ah, probably it’ll pass in a minute or two,” you say to yourself, but the blinding rain just keeps coming and coming. Pretty soon you realize that the water on the roadway is getting deep, dangerously deep. You can’t see more than a few inches out of any of the windows because of the intense downpour. A few minutes later, you feel the car being moved, but you’re not moving it. The acceleration increases. The car goes sideways and is swept off the road. Where it comes to a stop may determine whether you and your family members live or die.

This is the unpredictability of flash flooding, and this summer it appears to be occurring more and more often in our area. On Saturday, five people were killed and two others - a 2-year-old toddler and her 9-month-old brother - were missing in the Washington Crossing area of Bucks County after their father’s vehicle was washed off a two-lane road. The children’s mother also died, but the father, a 4-year-old son and the children’s grandmother survived. A massive search has been underway since Saturday to recover the children’s bodies.

The following day, flash flooding overwhelmed and caused extensive damage to parts of Lower Mount Bethel Township, north of Easton, and Forks Township, both in Northampton County, causing major damage. Just across the Delaware River in Warren County, New Jersey, up to 12 inches of rain fell in a short time causing major damage but no injuries. Gov. Phil Murphy declared a state of emergency for Warren and several other Garden State counties.

Earlier this month, torrential downpours made some roads in the eastern Poconos impassable, but, luckily, no one was hurt or killed. The previous week, flash floods inundated portions of northern Berks County in the Temple area, about a 10-minute drive from Kutztown. At more than two inches of rain per hour, the swift-moving water swept up everything in its path, including foundations of homes, sidewalks and parts of roadways. Before it was done, more than eight inches of rain had fallen in some parts of the county.

So what exactly is flash flooding, and what causes it? The National Weather Service reminds us that most flood deaths are caused by flash floods, which often take residents and motorists by surprise.

A National Weather Service spokesman said most people are unaware of how potentially dangerous flash flooding can be, and the fact that it can occur within minutes makes it deceivingly dangerous.

“Flash floods can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels,” the Weather Service advises. “Rapidly rising water can reach heights of 30 feet or more.”

This is the second summer since 2021 where there has been loss of life because of flash flooding in the Bucks, Pennsylvania-Hunterdon, New Jersey region bordering the Delaware River. On Sept. 21, 2021, rainfall measured nearly 10 inches and resulted in the death of six people - three from Pennsylvania and three from New Jersey - from flash flood waters near Lambertville, New Jersey. During that same storm - remnants of Hurricane Ida - flash floods led to evacuations and water rescues in Schuylkill County.

Most flash flooding is caused by slow-moving thunderstorms repeatedly attacking the same area or heavy rains from the aftermath of hurricanes and tropical storms.

Even six inches of fast-moving floodwater can knock you off your feet. Your car will float away when water is at a depth of two feet. The National Weather Service has this lifesaving advice: “If you come upon floodwaters, stop. Turn around. Go another way. Never try to walk, swim or drive through swift-moving water that covers the roadway.” If a flash flood strands you in your vehicle, “abandon it immediately and seek higher ground,” advises the National Oceanic and Atmospheric Administration.

By BRUCE FRASSINELLI| tneditor@tnonline.com

The foregoing opinions do not necessarily reflect the views of the Editorial Board or Times News LLC.