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Monday, July 14, 2025

Flash Flooding and The PIC

Into the Mystic


It has been awhile since I have posted on the topic of the PIC. Truth be told there has been so many examples and many of them are repeats. Multiple power outages. Multiple data breaches. Many intensified storms and floods. Examples aging infrastructure failures. The list is extensive. 


My warnings and calls for implementing failure resistance never seem to reach the correct ears. 


Here and now I am writing about the massive flash flooding event of July 4 in Kerrville, Texas.  The rainfall total is a measure of magnitude in inches of rain. Beyond that number is several convergent factors which led to the tragedy of hundreds of people swept away in the currents and drown. 


My days of study was in hydrology in college and working with the Army Corps of Engineers, watershed computer model, called STORM. 


Two of the intensity factors for river flooding are how fast the rain falls (in inches per hour) and how all the tributaries combine to make peak flow. 


The Guadalupe River is a known flood hazard from many decades past. FEMA had produced flood hazard maps for the river reaches where the most life was lost. 30 years ago there was a major flooding incident in nearly the same locations. 


These maps are drawn based on topography and both upstream and down stream conditions. The maps do not consider existing or future land use. Those conditions are a matter of private property rights. Local authorities can permit or deny permits to build structures of various uses in the flood zone. 


These regulations are supposed to protect land owners from their short sighted plans. Likewise they are supposed to protect the public from unknowingly residing in the danger zones. 


During many decades of continuous occupation a Christian Girls Camp grew up next to the river. Camp Mystic, Guadalupe site was the one where 27 children died in the flood. Hundreds of others escaped the torrents because their sleeping quarters were further up the river bank. 


Other people who lost their lives were also residing in structures which were located in the flood plain. 


This rainfall event was labeled as a One Hundred Year event. That nomenclature is not a suggestion the flood only happens once a century but is a measure of rainfall. The flooding is related to those other factor mentioned above. The measure of how deadly a floor may be relates to what time of day it happens, the season and how many people choose to be in the flow channel when it does. 


The owners of Camp Mystic knew their camp location was dangerous. They even petitioned to FEMA to revise its flood maps to exclude some of its existing building from the constraints of the regulations. Additional flood insurance was thereby avoided. Buildings could be kept where they were. New construction could be added in areas known to be in peril of flooding. 


The claims some officials make that they did not know a flood of this magnitude could happen may indeed be true but they chose to ignore the possibilities. 


The town also chose to not foot the costs of a flood warning system. The proposal was put up to the voters to make a decision they were wholly unqualified to make. They voted their personal interests of saving money and not trusting the federal government to plan and build the warning system. A lot of bucks got passed.


Flash floods are nothing new. Their intensity and frequency is.  Every year uninformed or stubborn people camp in dry washes of New Mexico and other arid states only to be caught in a sudden flood event. People continue to build their homes where the scenery seems pleasant. They too get washed away when nature turns against them. Of course not everyone gets flooded in their poor decisions. Therein lies the fragility which results in the Collapse. They believe they will be the ones who don’t get killed in the flood. Probability suggests they can live in a hazardous location for years or decade s and not be present when the catastrophe comes.