Just before sunset on the evening of Sept. 6, 2013, two clusters of thunderstorms were approaching western Collier County. One was drifting or reforming as it moved southward toward me (northern Collier County) from Lee County (Fig. 1). The second thunderstorm cluster was to my south and was advancing slowly northward (Fig. 2). It was easy to see and hear the storms approaching from the two disparate directions. Radar imagery showed the two thunderstorms, as well (Fig. 3)
Much as what happens when two waves at the beach approach each other, merge and push water higher (Fig. 4 and Fig. 5), I knew these two thunderstorms were going to generate a big storm over western Collier County. What I didn’t realize, as I shared this hypothesis with my wife, was how big the new storm cluster would be.
Shortly after 8 p.m. E.D.T., the loudness of the thunder increased markedly, while the brightness of the cloud-to-ground lightning strikes intensified. The strikes got much closer, as well. It didn’t take long for the nearly continuous flashing to generate very loud, almost simultaneous, crashes of thunder.
Then, raindrops started to splatter onto our pool cage. Initially, they fell sporadically. It didn’t take long, though, for the deluge to ensue.
This onslaught of lighting, thunder and intense rainfall continued for what seemed to be an eternity. One reason for this was that one of the early nearby flashes produced the dreaded power surge that, so often, knocks out cable and Internet service. Our lights only flickered off briefly. However, watching the rest of the TV movie we had ordered became impossible.
Off to bed early, I knew the thunderstorm was still underway. Sleep managed to overtake me quickly. My dog, however, was much more uncertain of the ongoing events. My wife, later in the day, told me that he sat up in bed during the whole storm before deciding it was safe to lie down.
I awoke before sunrise on Saturday, Sept. 7, 2013. Curious to see how much rain had fallen, I dressed quickly and went outside to check my official four-inch diameter COCORAHS (Community Collaborative Rain, Hail and Snow Network) rain gauge. Shining my iPhone flashlight onto the gauge, I gasped. The gauge was nearly full (Fig. 6).
Since there was no way I was going to pour water from the overflow part of the gauge into the measuring tube outside, I brought the gauge inside.
The gauge sits nearly ten inches tall. So, when I finally tallied the component measurements, the 9.45 inches of rainfall didn’t shock me.
However, I questioned the validity of my observation because it seemed so absurd. “Was there excessive splatter from nearby areas?”, I asked myself. “Could anything else have affected this rainfall measurement?”
The flooded woodlands that sat behind my house provided all the testimony that I needed (Fig. 7). Viewing lake levels, while walking my dog, provided further evidence of the measured rainfall (Fig. 8). Fig. 9 shows a bird that has landed on a wall that previously had separated two ponds with different water levels.
Morning TV news reports talked about four to six inches of rainfall across northern Collier County and resulting street flooding. I thought I knew the whole story now (well, almost, that is).
It took until later in the day to view the radar at the time of peak storm intensity (Fig. 10) and twenty-four radar/observer based rainfall maps (Fig. 11 and Fig. 12). Both showed a large, almost circular, bull’s eye centered over my neighborhood in north Naples. Almost all of the flooded roadways and other flood situations were nicely nestled within or adjacent to that area.
Driving around north Naples and nearby parts of Collier County, during the afternoon of Sept. 7, 2013, it was easy to see the flooded drainage canals, flooded front yards and flooded roadways (Fig. 13, Fig. 14 and Fig. 15). It was also easy to see how community lakes had risen to, most likely, unprecedented recent levels.
I can only imagine what would have happened if that thunderstorm cluster had parked itself atop the places in north Fort Myers, already flooded due to two months of unrelenting rainfall (Fig. 16).
After realizing that the storms lasted but a scant three hours on the evening of Sept. 6, 2013, it was easy to envision what Noah must have thought, if such thunderstorms had lasted forty days and forty nights. That translates to about 80 inches of rain per day times 40 days or some 3200 inches of rain. We are talking 250 feet of rainfall. That could be one major flood!
© 2013 H. Michael Mogil