https://therepository.org/hook-echo/Natural disasters read off the instruments that saw them: NEXRAD radar, satellite and the damage survey.enhttps://therepository.org/hook-echo/ep18-mayflower-vilonia-tornado-debris-on-radar-for-an-hour/https://therepository.org/hook-echo/ep18-mayflower-vilonia-tornado-debris-on-radar-for-an-hour/Mon, 02 Nov 2026 13:30:01 +0000On 27 April 2014, a tornado crossed 41 miles of central Arkansas, through Mayflower and Vilonia, and killed 16 people, the deadliest single tornado in the state since 1968. The Weather Service radar at Little Rock was 12 to 26 miles away the whole time. We measured its debris signature scan by scan: debris in every scan from 7:06 to 8:06 PM, over Mayflower in the scan that began at 7:29, the minute a Tornado Emergency named the town. Vilonia had been hit three years and two days earlier. And thehttps://therepository.org/hook-echo/ep17-hurricane-helene-the-river-gauge-that-beat-1916/https://therepository.org/hook-echo/ep17-hurricane-helene-the-river-gauge-that-beat-1916/Fri, 30 Oct 2026 14:00:32 +0000Hurricane Helene came ashore near Perry, Florida, on the night of 26 September 2024, a Category 4. Its worst flooding came almost 400 miles away, in the mountains of western North Carolina. On the French Broad River at Asheville, the USGS gauge, with continuous records since 1895, peaked at 24.82 feet, 1.72 feet above the Great Flood of 1916. But the flow was 113,000 cubic feet per second against 110,000 in 1916: by water, the same flood. Upstream, on the Swannanoa, the gauge record holds a singhttps://therepository.org/hook-echo/ep16-ef-scale-why-no-tornado-was-rated-ef5-for-12-years/https://therepository.org/hook-echo/ep16-ef-scale-why-no-tornado-was-rated-ef5-for-12-years/Thu, 29 Oct 2026 00:31:49 +0000From Moore, Oklahoma, on 20 May 2013, to Enderlin, North Dakota, on 20 June 2025, no tornado in the United States was rated EF5: 12.1 years, the longest gap since records began in 1950. The Enhanced Fujita scale is read from damage, not measured. On its table for houses, the worst damage a home can show, the slab swept clean, has an expected wind of 200 mph: the top of EF4. On the old Fujita scale, the same slab was F5. When a mobile radar measured at least 295 mph near the ground at El Reno in https://therepository.org/hook-echo/ep15-1906-san-francisco-earthquake-a-road-moved-20-feet/https://therepository.org/hook-echo/ep15-1906-san-francisco-earthquake-a-road-moved-20-feet/Tue, 27 Oct 2026 13:00:02 +0000The San Francisco earthquake of 18 April 1906 offset a road near Point Reyes Station by 20 feet. A year later, the Coast and Geodetic Survey re-measured its network of hilltop stations and found the ground had moved miles from the fault too: the Farallon lighthouse, 23 miles west of it, by 5.8 feet. From those surveys Harry Fielding Reid of Johns Hopkins worked out the theory of elastic rebound, still the model of the earthquake cycle. We redid the arithmetic from the 1908 tables: the survey andhttps://therepository.org/hook-echo/ep14-hurricane-andrew-category-5-ten-years-late/https://therepository.org/hook-echo/ep14-hurricane-andrew-category-5-ten-years-late/Sat, 24 Oct 2026 13:00:38 +0000Hurricane Andrew crossed South Florida at 5:05 AM EDT on 24 August 1992 and was rated a Category 4 for ten years. In August 2002 the National Hurricane Center raised it to a Category 5, 145 to 165 mph, and the number that moved it had been measured that night: a 162-knot wind at 10,000 feet, an hour before landfall. Every surface instrument that could have confirmed it failed or stopped before the peak, and the Miami radar was blown off the roof. We measured the eye ourselves on the Melbourne Dohttps://therepository.org/hook-echo/ep13-tuscaloosa-2011-13-minutes-missing-from-the-radar/https://therepository.org/hook-echo/ep13-tuscaloosa-2011-13-minutes-missing-from-the-radar/Thu, 22 Oct 2026 13:15:00 +0000On 27 April 2011 an EF4 tornado crossed Tuscaloosa and the edge of Birmingham, Alabama, on the ground for 80.68 miles; the National Weather Service counts 65 dead. The one radar that watched it from 70 km away has a single hole in its archive that day: 13 minutes, from 5:42 to 5:55 PM CDT, over the stretch through Concord and Pleasant Grove. We listed every scan it saved and measured what fell inside the gap. National Guard aerial video shows the path.https://therepository.org/hook-echo/ep12-hurricane-camille-the-record-from-a-home-barometer/https://therepository.org/hook-echo/ep12-hurricane-camille-the-record-from-a-home-barometer/Tue, 20 Oct 2026 13:00:17 +0000Hurricane Camille came ashore near Waveland, Mississippi, at about 11 PM on 17 August 1969, one of only four Category 5 hurricanes on record to hit the U.S. mainland. For 45 years the official record said 190 mph and 909 millibars. In 2014 a NOAA reanalysis changed it to 175 mph and 900 millibars: less wind, a deeper center. Neither number at the center was read by a government instrument. The 190 was an estimate made by an aircraft crew looking at the sea, and the landfall pressure came from a https://therepository.org/hook-echo/ep11-rolling-fork-tornado-what-the-radar-saw-in-the-dark/https://therepository.org/hook-echo/ep11-rolling-fork-tornado-what-the-radar-saw-in-the-dark/Sun, 18 Oct 2026 13:15:19 +0000On the night of 24 March 2023, a tornado crossed Rolling Fork, Mississippi, at 8:03 PM, 45 minutes after sunset. The final survey estimated its peak wind at 195 mph, and the Storm Prediction Center lists it as the strongest tornado of 2023 in the United States. The Weather Service radar at Brandon, 109 km away, scanned it every six minutes. We measured every scan ourselves: the radar saw debris in four of them. The tornado was on the ground for 71 minutes. FEMA drone footage shows Rolling Fork thttps://therepository.org/hook-echo/ep10-hurricane-harvey-2017-the-gauge-that-caught-60-inches/https://therepository.org/hook-echo/ep10-hurricane-harvey-2017-the-gauge-that-caught-60-inches/Fri, 16 Oct 2026 13:00:19 +0000Hurricane 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 shhttps://therepository.org/hook-echo/ep09-alaska-1964-earthquake-the-coastline-that-rose-38-feet/https://therepository.org/hook-echo/ep09-alaska-1964-earthquake-the-coastline-that-rose-38-feet/Thu, 15 Oct 2026 13:00:13 +0000On Good Friday, 27 March 1964, a magnitude 9.2 earthquake, the largest ever recorded in the United States, shook south-central Alaska for as long as four and a half minutes. Along hundreds of miles of coast the land itself moved: some shores sank as much as 8 feet, others rose as much as 38. The nearest seismograph went blind and the tide gauges in the zone were destroyed, so the movement was measured with barnacles. Federal film from 1964 to 1966 shows Anchorage, the waterfronts and the shores.https://therepository.org/hook-echo/ep08-mayfield-2021-the-tornado-that-stayed-down-165-miles/https://therepository.org/hook-echo/ep08-mayfield-2021-the-tornado-that-stayed-down-165-miles/Wed, 14 Oct 2026 13:00:11 +0000On the night of 10 December 2021 one tornado crossed western Kentucky for about 165 miles, in the dark, at about 60 miles an hour. At about the minute it reached Mayfield, the National Weather Service office in Paducah lost its power. Three radars kept recording, and we measured every scan: from 8:59 to 11:45 PM, at least one of them saw debris on the tornado's path in every scan. FEMA drone footage shows Mayfield and Dawson Springs days later.https://therepository.org/hook-echo/ep07-katrina-2005-the-record-surge-no-gauge-recorded/https://therepository.org/hook-echo/ep07-katrina-2005-the-record-surge-no-gauge-recorded/Mon, 12 Oct 2026 13:00:21 +0000On 29 August 2005 the sea rose about 25 feet over Waveland and Bay St. Louis, Mississippi. The NOAA tide gauge at Waveland sent its last reading at 4:12 in the morning: eight feet. Its neighbours at Biloxi and Ocean Springs went silent too, all before landfall. The highest storm surge ever recorded on the US coast was read off walls, weeks later. Military footage from Waveland and Biloxi shows what it left; we read the gauges and the 400 high-water marks ourselves.https://therepository.org/hook-echo/ep06-hook-echo-what-the-tornado-shape-on-radar-really-means/https://therepository.org/hook-echo/ep06-hook-echo-what-the-tornado-shape-on-radar-really-means/Sun, 11 Oct 2026 13:30:40 +0000A security camera at Chickamauga Lock, Tennessee, filmed an EF2 tornado crossing the yard on 26 October 2010 -- and the radar 84 km away drew no hook at all. The hook echo, the shape this channel is named after, was first photographed by accident in Champaign, Illinois, in 1953. We render hooks from five radars, including one over Oklahoma City in 1998 that never produced a tornado, and go through the study that drove instrumented cars into thirty of them.https://therepository.org/hook-echo/ep05-joplin-2011-the-tornado-warning-17-minutes-early/https://therepository.org/hook-echo/ep05-joplin-2011-the-tornado-warning-17-minutes-early/Sat, 10 Oct 2026 13:00:19 +0000On 22 May 2011 the National Weather Service warned all of Joplin, Missouri, 17 minutes before a tornado touched down -- more than the national average. It still became the deadliest single US tornado since records began in 1950. National Guard footage shows the path; the Springfield radar, rendered from NOAA's raw archive, shows what the forecasters could see, and from how high.https://therepository.org/hook-echo/ep04-hurricane-michael-2018-the-data-made-it-a-category-5/https://therepository.org/hook-echo/ep04-hurricane-michael-2018-the-data-made-it-a-category-5/Fri, 09 Oct 2026 13:00:00 +0000Hurricane Michael came ashore at Mexico Beach, Florida, on 10 October 2018, announced as a Category 4. Six months later the National Hurricane Center made it a Category 5 -- by three knots. FEMA footage shows what it left. We go through every instrument the NHC weighed, and read the raw record of the USGS sensor strapped to the Mexico Beach pier, which went under water at 17:20 UTC.https://therepository.org/hook-echo/ep03-kilauea-2018-the-volcano-that-fell-in-on-itself/https://therepository.org/hook-echo/ep03-kilauea-2018-the-volcano-that-fell-in-on-itself/Wed, 07 Oct 2026 12:45:07 +0000In 2018 the summit of Kilauea, Hawaii, collapsed 62 times in three months while lava poured out of Leilani Estates, 40 km away. USGS footage shows both ends. We downloaded the raw records -- the USGS earthquake catalogue, a seismometer on the caldera rim and a GPS station that sank almost two metres -- and measured how the volcano emptied itself.https://therepository.org/hook-echo/ep02-moore-2013-the-day-radar-saw-the-debris/https://therepository.org/hook-echo/ep02-moore-2013-the-day-radar-saw-the-debris/Tue, 06 Oct 2026 03:30:14 +0000On 20 May 2013 a mile-wide EF5 tornado crossed Newcastle and Moore, Oklahoma. National Guard footage shows what it left. The Oklahoma City radar, upgraded to dual polarization 225 days earlier, saw something no radar there could see in 1999: the debris itself, lifted almost four miles into the storm. We measured it scan by scan from NOAA's raw archive.https://therepository.org/hook-echo/ep01-bridge-creek-moore-1999-how-radar-clocked-301-mph/https://therepository.org/hook-echo/ep01-bridge-creek-moore-1999-how-radar-clocked-301-mph/Mon, 05 Oct 2026 11:25:22 +0000On 3 May 1999 a truck-mounted Doppler radar measured winds of about 301 mph, give or take 20, inside the tornado that crossed Bridge Creek and Moore, Oklahoma. In 2021 the same scan was reprocessed to 321 mph. We rendered the federal radar's own scans of that evening, straight from NOAA's raw archive, to show what each instrument could measure, and what it could not.