The Repository Hook Echo

Hurricane Harvey 2017: The Gauge That Caught 60 Inches

October 16, 2026 · Runtime 15:19 · Watch on YouTube

Hurricane Harvey came ashore near Rockport, Texas, as a category 4 on 25 August 2017, and then stalled over the Texas coast for four days. Near Nederland, a rain gauge run by a county drainage district collected 60.58 inches, the largest tropical-cyclone rain total ever measured in the United States. About a mile away, the Weather Service gauge at the airport recorded 47.52. Federal footage from the Coast Guard, Customs and Border Protection, the Army Corps of Engineers and the National Guard shows Houston, Addicks and Barker, Beaumont and Rockport.

Chapters

  1. 0:00 Houston, August 2017
  2. 0:44 The question
  3. 0:59 Landfall at Rockport
  4. 1:44 Four days in one place
  5. 2:21 Houston's worst night
  6. 3:41 What radar measures
  7. 4:25 The map ran out of colors
  8. 4:43 Addicks and Barker
  9. 6:02 Rivers and lakes at record
  10. 7:03 The rain moves east
  11. 7:20 Our measurement: the airport gauge
  12. 8:15 The record gauge
  13. 9:32 Two gauges, a mile apart
  14. 10:13 64.58, then 60.58
  15. 10:53 What the radar estimated
  16. 11:25 The ground that sank
  17. 12:08 Our GPS check, and why it fails
  18. 12:35 How rare
  19. 13:24 The cost
  20. 14:21 What the record supports
  21. 14:56 Next: Rolling Fork, 2023

Transcript

Houston, August 2017 0:00

This is Houston, during Hurricane Harvey, at the end of August 2017. The storm came ashore as a category four, and then it stopped moving, and rained on the same coast for four days. Near Nederland, Texas, one rain gauge collected sixty point five eight inches, the most ever measured from a tropical storm in the United States.

That number did not come from a satellite or a radar. It came from a gauge run by a county drainage district. About a mile away, an official Weather Service gauge, at the airport, recorded forty-seven and a half. And the first number published for the record gauge was not sixty point five eight. It was sixty-four point five eight.

The question 0:44

So here is the question this episode answers. How do you measure sixty inches of rain, when an ordinary rain gauge fills up at about twelve? And when two instruments a mile apart disagree by thirteen inches, which one is the record?

Landfall at Rockport 0:59

Harvey came ashore at ten at night on August 25th, at the northern end of San Jose Island, about five nautical miles east of Rockport. The Hurricane Center estimates sustained winds of a hundred and fifteen knots, about a hundred and thirty miles an hour, and a central pressure of nine thirty-seven millibars. This is Rockport, from the air, three days later.

This is the Corpus Christi radar on the night of landfall. The bright ring is the eyewall, the band of the strongest wind and rain. The quiet hole inside it is the eye, coming onshore. For a hurricane, that is the usual ending. Over land, it loses its fuel and weakens as it moves inland. Harvey did not move inland.

Four days in one place 1:44

The Hurricane Center's report puts it in one sentence: the storm stalled, with its center over or near the Texas coast for four days. It made a slow loop on August 26th and 27th, then drifted east. This is four days of the Houston radar, one scan per hour. The bands keep arriving from the Gulf, over the same ground.

Here is the map. Landfall near Rockport. Houston, about two hundred and fifty kilometers up the coast. And at the far end, near the Louisiana line, Nederland and Port Arthur, where the largest number would be measured.

Houston's worst night 2:21

The worst night in Houston was the night of August 26th into the 27th. This is the Houston radar from nine that night to three in the morning, with band after band crossing the city. Harris County runs its own network of rain gauges, through its Flood Control District, and its final report lists the peaks.

Six point eight inches in a single hour. Twenty-five point six in a day. Thirty-five point two in two days. And forty-seven point four in four days, at the gauge where Clear Creek crosses Interstate 45. The district calculates that four-day total as ninety-five percent of the probable maximum precipitation, the most rain engineers consider physically possible there.

Add it up over the whole county. The district's report estimates that about one trillion gallons fell on Harris County in those four days. Spread evenly, that is thirty-three point seven inches of water over all seventeen hundred and seventy-seven square miles of the county.

Houston had seen hard rain before. In 2001, Tropical Storm Allison dropped more rain than Harvey in six, twelve and twenty-four hours, the district's report notes. Harvey's difference was time. Over two days it beat Allison by six inches, and over four days by almost nine.

What radar measures 3:41

The radar never measured any of that rain directly. A radar measures echo, the energy that bounces back from the drops, and a formula turns that echo into a rain rate. The Houston radar stayed on the air for the entire storm. But when NASA researchers later checked its dual-polarization estimates against more than two hundred county gauges, most of the methods they tested came out about a quarter low.

Notice which way that comparison runs. The gauges were the reference. The radar was being checked against them, not the other way around. A radar sees the whole storm at once. A gauge sees one spot, a few inches across. But only the gauge holds the water.

The map ran out of colors 4:25

On Monday, August 28th, the Weather Service had to change its own map. Its rainfall color scale topped out at more than fifteen inches, and the rain had gone past it. So it added two new shades of purple, one for twenty to thirty inches, and one for more than thirty.

Addicks and Barker 4:43

West Houston has two flood-control reservoirs, Addicks and Barker, built by the Army Corps of Engineers more than seventy years ago. Most of the time they are dry fields, and the water passes through. On August 28th, the Corps announced it was starting releases immediately, because both reservoirs were rising more than half a foot per hour.

We read the Geological Survey's own gauge in the Addicks pool. About sixty-nine feet on August 24th, before the rain. A hundred and one by the 27th. And a hundred and nine point oh nine on August 30th, more than six feet above the record set the year before. The county's report gives a hundred and nine point one.

At seven fifteen on the morning of August 29th, the Addicks pool reached a hundred and eight feet. At that level, water began flowing around the north end of the dam, over natural ground, uncontrolled, for the first time ever. The county notes it was also the first time homes upstream of the reservoirs had flooded from the rising pools themselves.

To protect the dams, the Corps raised the releases to a combined sixteen thousand cubic feet per second, the highest since the outlets were fully gated, in 1963. At peak, the two pools together held about a hundred and twenty-six billion gallons of water.

Rivers and lakes at record 6:02

The rivers kept the record too. The Geological Survey looked at seventy-four stream gauges in Texas with long histories. At forty of them, Harvey produced the largest flow ever recorded. Lake Houston, northeast of the city, rose to fifty-three point one feet, past its record from 1994.

Some instruments did not survive the flood they were measuring. The county's warning system lost seven gauges completely, and five more were damaged, mostly the devices that measure water level. Still, three hundred and seventy-five thousand readings of rain and water level reached the system from the field. And one Geological Survey station near Beaumont was itself submerged and damaged.

The largest flow of all was east, at Pine Island Bayou, near Beaumont: a hundred and eighty-two thousand cubic feet per second, on August 30th. Because by then, the heaviest rain had moved east, toward Beaumont and Port Arthur, at the Louisiana line.

The rain moves east 7:03

This is the Lake Charles radar, in Louisiana, which covers that corner of Texas, through August 29th. Harvey's center had drifted back over the Gulf, toward its last landfall, in Louisiana. All that day, one band after another lined up over the same strip of land.

Our measurement: the airport gauge 7:20

Between Port Arthur and Nederland sits the regional airport, with an official Weather Service station that reports every hour. We pulled its hourly record from NOAA's archive. At the midnight that began August 29th, it had about eighteen and a half inches for the storm. At the next midnight, forty-four and a half.

Twenty-six inches fell at that airport on August 29th alone. The worst hour came late that night. In the hour before midnight, the gauge recorded four point two nine inches. This is the Lake Charles radar during that hour, with the airport marked.

A daily total hides the shape of the day, and the hourly record shows it. On August 29th, the airport gauge recorded at least an inch of rain in twelve separate hours. Not one burst. A whole day of it, hour after hour, on the same spot.

The record gauge 8:15

About a mile from the airport gauge stood another one. It belongs to Jefferson County Drainage District Number Seven, the agency that keeps the ditches and pumps of this flat coast working. The Hurricane Center's report prints a photograph of it, because this is the gauge that set the record.

Its daily totals are in the Hurricane Center's data. One point seven five. Three point four three. Thirteen point three six. Seven point nine seven. Then, on the day listed as August 29th, thirty-one point three five inches. Then two point seven one. Sixty point five eight in all.

Before Harvey, the record for a tropical storm in the United States was fifty-two inches, from Hurricane Hiki, in Hawaii, in 1950. On the mainland it was forty-eight, from Tropical Storm Amelia, in Medina, Texas, in 1978. During Harvey, eighteen readings passed forty-eight inches, and seven passed fifty-two.

The record gauge was not alone. Another district gauge, near Groves, about five miles to the east, collected sixty point five four. Two gauges, one agency, four hundredths of an inch apart.

Two gauges, a mile apart 9:32

Now put the airport next to them. Forty-seven point five two, about a mile from the record gauge. The Weather Service's cooperative gauge in Port Arthur, forty-four point five five. Two networks, a few miles apart, more than thirteen inches apart.

The record does not say which gauge was closer to the truth, and it would be wrong to guess. Rain this heavy is patchy, and one band can sit over one gauge and miss another. But instruments also struggle in rain like this. The Hurricane Center notes that many standard gauges filled to their limit, about twelve inches, and could not be emptied, because the rain came too fast.

64.58, then 60.58 10:13

There is one more wrinkle. In September 2017, the Port Arthur newspaper reported that the district's gauge near the airport had recorded sixty-four point five eight inches, a number released by the Weather Service. The same article said the data would be reviewed, to check the calibration and look for obstructions.

The Hurricane Center's final report, in 2018, lists sixty point five eight for that gauge, and sixty point five four for Groves, which had first been reported at sixty-three point one four. The documents we found do not say what changed. They only show that the number went down by four inches before it became the record.

What the radar estimated 10:53

And what did the radars say? The Hurricane Center writes that the combined radar estimates reached sixty-five to seventy inches in southeastern Texas, near Port Arthur, where there were few gauges. It treats those numbers as the most rain that could have fallen there, not as a measurement.

Across the line in Louisiana, the gap was wider. The radar suggested about forty inches. The highest gauge there measured twenty-three point seven one. Where there is no gauge, there is no record, only an estimate.

The ground that sank 11:25

There was one more instrument that weighed the rain, and nobody built it for that. Around Houston, GPS stations measure the height of the ground to the millimeter. A 2018 study of two hundred and nineteen of them found that one day after landfall, stations around Houston sank by up to twenty-one millimeters. The ground was bending under the weight of the water.

From that sinking, the study calculated how much water was sitting on the land. Of about ninety-five cubic kilometers of rain, roughly a third, twenty-five point seven, was held on land at once. The rest drained to the Gulf at about eight cubic kilometers a day. Over about five weeks, the ground rose back.

Our GPS check, and why it fails 12:08

We tried to repeat this ourselves, with the daily positions published by the Nevada Geodetic Laboratory. Eighty-one stations from Houston to the Louisiana line dropped a median of eleven millimeters on August 28th. But sixteen stations near Dallas, far outside the rain, dropped seven the same day. So our quick check cannot separate the water from noise shared by the whole network. The number on screen is the study's, not ours.

How rare 12:35

How rare was it? Different studies measure different things. Kerry Emanuel, at MIT, looked at about twenty inches of rain, averaged over the Houston area. In the climate of 1981 to 2000, he estimated that as roughly a once in two thousand year event. By 2017, about once in three hundred and twenty-five years.

A second study, by Geert Jan van Oldenborgh and colleagues, used a different gauge: the cooperative station at Baytown, east of Houston, with forty-one point zero seven inches in three days. They put the return period of that three-day total at more than nine thousand years, in the current climate. And notice the choice. The paper says amateur stations recorded even higher amounts, and were not used.

The cost 13:24

Harvey killed at least sixty-eight people directly, all in Texas, thirty-six of them in Harris County. All but three of those deaths came from freshwater flooding, not from the storm surge. About thirty-five more deaths are counted as indirect. In Harris County alone, government crews rescued more than sixty thousand people.

In Harris County, the district estimates that a hundred and fifty-four thousand homes flooded. Sixty-eight percent of them were outside the hundred-year floodplain, the line that is supposed to mark the risky ground. The map of risk was drawn from the rain of the past. Harvey's rain was not on it.

NOAA's estimate of the damage is a hundred and twenty-five billion dollars. Adjusted for inflation, that makes Harvey the second costliest hurricane in United States history, behind Katrina. More than three hundred thousand structures flooded in southeast Texas, along with up to half a million cars.

What the record supports 14:21

Here is what the record supports. Harvey's number is not a model and not a radar estimate. It is water in a gauge: sixty point five eight inches, a mile from another gauge that caught thirteen inches less, and four inches below the first number anyone published.

The radar shows where the rain fell. The rivers, the reservoirs and even the bending ground show how heavy it was. Only the gauge says how much. And on that coast, in those five days, the gauge was a drainage district's, in a town most of the country had never heard of.

Next: Rolling Fork, 2023 14:56

Next, a tornado at night. On March 24th, 2023, a tornado about three quarters of a mile wide crossed Rolling Fork, Mississippi, in the dark, and the Weather Service rated it EF4. That is the next episode. Rolling Fork, 2023: the tornado that crossed a town in the dark.

Description and sources

The record is water in a container: the National Hurricane Center credits 60.58 inches to Jefferson County Drainage District gauge 8920, near Nederland, with 31.35 on the day listed as 29 August; a second district gauge at Groves caught 60.54. Our reading of NOAA's hourly archive for the airport gauge, about a mile away, gives 47.52 inches, 26.03 on 29 August and 4.29 in the hour before midnight. The record gauge was first reported at 64.58; the 2018 report lists 60.58, and we found no document explaining the change. Radar estimated 65-70 inches near Port Arthur, where gauges were few. Addicks Reservoir reached 109.09 ft (USGS gauge, our reading) and spilled around its dam for the first time; GPS stations around Houston sank up to 21 mm under the water's weight.

PRIMARY SOURCES

ARCHIVE PLATES — public-domain documents, with author, date, archive and licence.

  • Figure 7. Picture of Jefferson County Drainage District rain gauge in | NOAA National Hurricane Center | public-domain

Hook Echo reads a disaster through the instruments that recorded it: radar, sensor, survey and report, with the primary sources above.

About the material. Video: U.S. Customs and Border Protection, U.S. Army Corps of Engineers, U.S. Coast Guard, U.S. Navy, Texas Military Department, Texas Army and Air National Guard (August-September 2017), and FEMA (Rolling Fork, March 2023), released through DVIDS. Radar: NOAA NEXRAD Level II from KCRP, KHGX and KLCH, rendered by Hook Echo from the raw data. The photograph of the record gauge is Figure 7 of the National Hurricane Center's report. The airport rain series, the Addicks pool series and the GPS check are our own readings of NOAA, USGS and Nevada Geodetic Laboratory public data. Every diagram is drawn in code from the sources listed. Nothing in this video is AI-generated imagery.

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