OC
[OC] The July 4 flash flood on the upper Guadalupe River (water level heights above normal)
This animation shows water levels on the upper Guadalupe River from midnight July 4, 2025, to 6 p.m. July 5 (local time). The flood killed 119 people in Kerr County, including 25 girls and two teenage counselors at Camp Mystic.
Data sources
Raw stream gauge data from the USGS was downloaded and processed to be consistent 5-minute data; it was then normalized to the average July water level at each station to get "height above normal."
This is great, I've never seen data presented like this before. One thing I'd suggest is to add a scale on the map. I'd like to know how far between the camp and the lake for instance. Miles AND kilometers please!
Yes, that's exactly what happened at the Center Point stream gauge. The gauge at Hunt (which is the second from the left) also failed after recording levels at 30' above normal.
I tested out a few ways of indicating gauge breaks, but all the things I tried ended up just highlighting the locations where there was no longer usable data. So I settled on fading out the bars where they had missing data points instead.
Raw stream gauge data from the USGS was downloaded and processed to be consistent 5-minute data; it was then normalized to the average July water level at each station to get "height above normal."
I am wondering why did you use JavaScript for data visualization? I ask because I almost exclusively use python, including visualizations. Is it easier in JavaScript?
Python is great for static visuals, or building movies frame-by-frame!
But if you're making an animation or want to have some web-based interactivity, it's worth using JavaScript because it allows you to take advantage of all the transitions and tweens of D3 and CSS (e.g., the bars don't jump up to the next position, they slide based on a given duration; the time flies out and fades out when it changes; the bars smoothly fade out to zero opacity when there has been no data at a gauge for more than 60 minutes, etc.).
You can build tweening into a python-driven animation, but it starts to feel a bit painful to track ancillary values like color and alpha for every element that's transitioning.
A lot of these transition effects are more apparent in the original graphic, which has an interactive time slider that you can scrub or use arrow keys on, roll-over tooltips, etc.
That original interactive graphic is really cool and overall it’s just a really cool and creative visualization combining the river map, gauges and time dimensions. If you’re interested I have some ideas to improve it, if not just ignore what follows. This is really good.
I think it’s somewhat hard to appreciate the speed of the water rise with the small clock in the footer and the minutes spinning by super fast. Slowing things down, repositioning / enlarging the clock and using higher contrast colors for the clock could help.
From a narrative perspective (if you want to go there) I’d love to see a couple of “checkpoints” called out, like:
* HH:mm heavy rain starts
* HH:mm river starts to rise at Camp Crystal
* HH:mm Camp Crystal gauges peak at xx feet
* etc
I'm surprised that the gauge capacity goes up to 45 ft. This is a rain of the century type situation. Hard to imagine things are overbuilt with that kind of foresight.
Unfortunately, I wasn't able to find out the specific type of water level sensor at that station.
If it's a bubbler or a pressure transducer, the sensor is measuring the water pressure in the stream, which increases with water depth. So, there's no limit to the gauge capacity per se (unless the hardware gets physically ripped out).
It could also be a radar mounted on the bottom of the bridge, and in this case, it's a pretty tall bridge. If you scoot around on the street view there, you can see the telemetry box for the gauge at the north end of the bridge.
Fascinating. I was picturing a really tall collection beaker. That bridge look a lot like this one. If so, the water level got above the tall bridge ☹️
Really cool visualization. Fascinating to see the effect of the lake, and I would’ve thought that the surge of flood water would be spread throughout the river more, rather than being concentrated in a small area. Guess that’s how much a water surge there was.
One of the best I’ve seen on here recently - nice stuff OP
Second, the effect of the Canyon Lake reservoir is definitely dramatic. It was at very low capacity, so it could soak up all that water. I wondered a lot how things would have looked downstream if the lake had been at its normal capacity instead.
Imagine the visualization if the city actually had water level monitors on the river that the local government refused since it was from “democrat funds”.
It was from major rain event (total rainfall up to 20" in spots) caused by the left-overs from Hurricane Barry. The moist air from the hurricane over the Gulf pushed up and over the Edwards Plateau and then just sat there, dumping rain.
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u/WheelerDan 2d ago
Legitimately beautiful, a rarity for this sub.