Like a confluence of extreme weather, geography and timing, the flood disaster in Texas caused

As a consequence of thunderstorms that were fed by the remains of the tropical storm, Barry Barry, the Hill Country in Texas, began tools that were used by the National Oceanic and Atmospheric Administration to recognize extreme precipitation, “maximized the color diagrams”.

The forecast models of a fall flood system called Flash and a program called Multi-Radar/Multi-Sensor-System, which recognizes strong precipitation-uses a cascading series of colors to communicate the severity of precipitation, said David Gagne, a national center for atmospheric scientists, which focuses on using machine learning to use the weather models improve.

The floods that the Hill Country recorded in Texas and killed more than 100 people were the result of a confluence of factors related to the storm dynamics and the local topography. Ultimately, they culminated in what Gagne described as the “worst case scenario”.

“All ingredients came together in the wrong place, at the wrong time, on a holiday weekend,” said Gagne. “This was at the top of the scale.”

While existing weather models can forecast fall floods in advance, even the best models have difficulty portraying the internal storm structure and predicting where the most difficult precipitation will occur within a few miles.

In this case, the colors outside the charts showed on Friday morning that the South Fork of the Guadalupe River scored a direct and longer goal.

Instead of continuing, the storms stalled.

The Texas State John Nielsen-Gammon said that the thunderstorms over the Texas Hill Country River were floating and dropping 10-12 inches in about six hours. The series of the storms “perfectly aligned with the South Guadalupe River Basin,” he said. The area is susceptible to floods and was filled with campers near the river. If the storm had been five miles in a different direction, it would not have produced as much destruction, he said.

It is difficult to know how much rain has fallen. The flooded basin has no rain knife, although in an area covered by the Texmesonet surveillance system that was created after a fall flood disaster that Wimberley, Texas, was created over the Memorial Day weekend in 2015. On Fridays Downpour On Friday there was a record comparison for this place and a storm that could be seen every 1,000 years, said Nielsen-Gammon.

While the forecasts of the National Weather service had largely warned of fall floods, meteorologists and predicted experts said that the best weather models could not predict exactly where the most intense precipitation would fall or that the deluge would stop over a flood -driven basin.

“Even the most detailed weather forecasts for weather forecasts are hardly able to solve individual convective storms,” ​​said Nielsen-Gammon and added that it would be “as good as impossible” to predict in advance, whether successive storms would be trained, intensive flooding in such a close geography, causing intensive floods.

Gagne checked the modeling tools that are available to the NWS forecasts. The most urgent warnings went out, he said when the two Noaa tools showed the rain rates to rise.

This only gave people a few hours to flee, provided they received the warnings about cell phone warnings, weather radio broadcasts or in any other way. Some residents probably didn’t get the alarm and Kerr County has no siren.

Texas leads the nation in flood deaths. From 1959 to 2019, the state counted 1,069 deaths of floods, such as Hatim Sharif, a professor of civil and environmental engineering at the University of Texas in San Antonio. That is 376 deaths than the nearest state during this time – Louisiana.

During the study period of six decades, the forecast office of the national weather service in San Antonio/Austin counted the second highest number of deaths in connection with floods in the country. Many of them took place in the Hill Country, which some call “Flash Flood Alley”.

The region is created by the Balcones Escarpment, a fault zone of the weather -given rock from Waco to Del Rio, which shares the state and can stop and catch heavy storms.

“The hilly country is basically the first terrain obstacle, the moist air from the golf experiences in the north moist. This delivers additional lifting and thunderstorms in the entire country of the Southern Hills,” said Nielsen-Gammon.

Sharif said, steep hills, narrow gorges that were carved out of the limestone, quickly convey water from smaller streams into larger and then into swollen rivers. In many areas there is only a few centimeters of flat ground on the basic rock. Narrow streams are etched in the floor.

“It doesn’t absorb a lot of water,” said Sharif. “It doesn’t take much time to flood these streams … you have this dissected area that efficiently moves water to the main stream.”

In a little more than 12 hours on Friday morning, the Guadalupe river rose about 20 feet on Hunt, according to a river measuring level, and converted a mild current into rapid rapids.

This article was originally published on nbcnews.com