Hurricane Celia 1970: Cat 4 for TX?

Discussion in 'Tropical forum' started by Josh Morgerman, Jan 14, 2011.

  1. Josh Morgerman

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    Hey, guys-- the Atlantic reanalysis work lately has gotten me in the mood to reexamine some other landfalling American cyclones. I just completed a close look at Hurricane Celia of 1970, which I posted on another forum, and I thought I'd share it here as well. Disagreement, debate, and dissenting opinions are all welcome-- especially from anyone who might happen to be part of the reanalysis project. :)

    Celia 1970: Reanalysis of the TX Impact

    This costly Texas hurricane has always been considered a Cat-3 impact. However, applying reanalysis methodologies described in other studies leads me to the conclusion that Celia was actually a Cat 4 at landfall in TX.

    Summary
    Celia formed in the NW Caribbean in late July. Moving NNW initially, it crossed the W tip of Cuba as a depression, then strengthened into a major hurricane as it pushed into the C Gulf of Mexico. Turning toward the WNW, Celia made a beeline for the TX coast as it steadily weakened. When just 250 mi off the coast, winds were only 75 kt—a Cat 1. However, the cyclone rapidly strengthened in the final 15 hrs before landfall, crossing the coast just N of Corpus Christi at ~1530 CST 03 August as a powerful hurricane. (The satellite picture below is from 2033Z-- just when the center was crossing the coast.)

    Storm surge flooding was not terribly extensive, and the storm’s small size and brisk movement precluded very heavy rainfall totals. The wind damage, however, was extreme—with swaths of Corpus Christi and nearby towns devastated by extremely high gusts. Celia was a true “wind event”—and one of the rare major hurricanes to deliver its best shot right to the heart of a major American city.

    At the time, Celia was the costliest hurricane in TX history, and it remained so until Alicia 1983.

    celiatrack.jpg

    celialandfallsat.jpg

    Pre-landfall Intensification
    The cyclone’s pre-landfall intensification was not anticipated. The central pressure dropped a whopping 43 mb in 15 hrs—from 988 mb just 250 mi off the coast to 945 mb at landfall.

    This qualifies as “explosive deepening” (defined as a drop of at least 2.5 mb/hr for at least 12 hrs).

    Landfall Point, Track, & Lowest Pressure
    The landfall point was just N of Corpus Christi—and I estimate it to be very close to Port Aransas, at the N side of the entrance to Corpus Christi Bay (see map—red marker “A”).

    “Hurricane Climatology for the Atlantic and Gulf Coasts of the United States” indicates a landfall point of 27.7N 97.1W, but this seems too far S. Surface obs strongly suggest the center moved along the N shore of the Bay. All of the pressure readings below 955 mb and all of the reports of lulls (the eye) came from the towns N of the Bay—marked on the map:

    • Aransas Pass: 949 mb, calm 30 mins
    • Ingleside: 945 mb, --
    • Gregory: 952 mb, calm 30 mins (1530 – 1600 CST)
    • Portland: -- mb, dead calm 30 mins
    • Taft: 952 mb, --
    • Odem: -- mb, calm 15 mins
    Given this, 27.8N 97.1W would seem the best estimate for the landfall point. (This value also conforms better with the 18Z 03 Aug and 00Z 04 Aug HURDAT fixes.)

    celiastrikezonemap.jpg

    Winds
    Celia’s winds had a violent, explosive quality that is highly unusual for hurricanes—and the cyclone was structurally odd, with the normally weaker left semicircle producing the most extreme conditions. Unfortunately, this left semicircle (the S eyewall) passed squarely over downtown Corpus Christi, with devastating results.

    The MWR mentions how sometimes in non-steady-state ‘canes, the isotach max and heaviest convection migrate cyclonically around the center. This was what happened with Celia, so that:

    to the north, there was a break in the eye wall; and very little rain fell. South of the hurricane center, in the region of heaviest convection, spectacular damage occurred from a cluster of high-energy winds of short duration that raked across the residential and business areas of the city from west to east within a period of less than 0.5 hr.
    Different eyewitnesses across Corpus Christi reported similar experiences: winds were sustained for several minutes at 60-70 kt when suddenly a tremendous gust exploded “like a rocket shell”, producing nearly all of the destruction in less than a minute. As per the NHC Preliminary Report, stopped electric clocks across the city suggest these blasts all happened within 15 minutes of each other.

    The aftereffects appeared to be tornado damage, but careful inspection showed it wasn’t. As per the MWR:

    These high-energy wind bursts produced streaky damage across the city of Corpus Christi with debris from the most heavily damaged structures being carried, in some instances, more than 1,000 yd downwind without evidence of any rotary character associated with the transport. Between these long streaks of major damage, there were areas of only minor damage, confined mostly to trees and ornamentals.
    Dr. Fujita mapped the F1/F2 damage, based on aerial photography by NASA and R.H. Simpson—although it should be noted that the damage ranged higher than F2. As per the NWS in Corpus Christi, “As a reference to the Fujita scale for tornado damage and wind speeds, widespread EF2 damage occurred across the Coastal Bend with pockets of EF4 damage.”

    celiawindswath.jpg

    Several stations reported winds well over 100 kt, with the highest being the Corpus Christi WSO (at the airport—see map), which measured 109 kt SW gusting to a whopping 140 kt! (This is one of the highest wind readings from an official reporting station in the USA during the modern era that I'm aware of.) Other peak values were:

    • Aransas Pass: 113 kt NNE
    • Port Aransas Coast Guard: 90 kt NNE G 110 kt
    • Gregory: 111 kt NNW G 120 kt (80 ft)
    (Unless noted, height and reliability of these readings is unknown—however, they appear in NHC and NWS official reports.)

    The wind field was not large. Extreme winds were confined to the immediate Corpus Christi Bay area, and the “Hurricane Climatology” paper estimates a RMW of only 9 n mi-- quite narrow.

    Damage
    Wind damage was very heavy. In Corpus Christi, close to 90% of the businesses and 70% of the homes were damaged, and in Aransas Pass, half the structures were severely damaged. Almost 9,000 homes were destroyed in TX. Excerpts from the NHC’s Preliminary Report capture some vivid anecdotes:

    • [*]A frightening evidence of wind forces involved was at the Woolco Shopping Center on South Staples Street. This new center, opened in July, was apparently of fine construction and was totally destroyed. The principal wall of the structure, about 18’ high, running approximately 50 yards in length, collapsed and the roof fell in. This main wall, with brick facing, was made of poured concrete with heavy steel reinforced rods. This wall was not simply blown over or blown in, but rather was torn in giant sections and displaced outward from the building. There was no evidence of an explosion.

      [*]In the Corpus Christi business district several tall buildings, some of whose exterior was faced mostly with glass, suffered heavily due to broken glass. In some buildings not a single pane of glass was left unbroken above the first two floors.

      [*]At Corpus Christi Airport two hangers [sic] heavily constructed with I-beams and steel trusses were totally destroyed with the heavy beams twisted and mangled in unbelievable fashion.

      [*]Celia provided a most dramatic example of what can happen to a trailer camp. Just northeast of the airport several hundred mobile homes, many of them of new modern design, were mangled and completely destroyed as if by a meat grinder with the debris being carried hundreds of yards eastward from the park.
    A great gallery of damage pics can be found here: http://www.srh.noaa.gov/crp/?n=celia1970#gallery

    Intensity Discussion & Verdict
    Celia’s central pressure at landfall is accepted as 945 mb.

    As per Andrew Hagen, reanalysis research uses pressure-wind relationship values derived by Brown et al. (2006), which are based on a “large sample size of aircraft data from 1998-2005.” Based on the Brown values, a strengthening 945-mb hurricane between 25N and 35N should have a max sustained wind of 115 kt. Keep in mind, Brown does not distinguish between slow and fast intensification—therefore, I would tend to view the 115 kt as a conservative value for Celia, which was explosively deepening.

    Next, there is the RMW. By all accounts, Celia was a small cyclone. The RMW value of 9 n mi is just over half the climatological norm of 17 n mi. As per Hagen: “Landsea et al. (2008) states that for landfalling U.S. tropical storms and hurricanes for which the RMW is significantly smaller (>50%) than the climatological value, 10 kt should be added to the pressure-wind relationship.” Since Celia’s RMW was a little larger than 50% of the climatological value, erring on the conservative side suggests the addition of 5 kt to the standard pressure-wind value.

    This yields a wind of 120 kt—and that is my estimate for Celia’s landfall intensity in TX.

    Numerical/theoretical analysis aside, the impressive surface observations at official reporting stations plus the extremely heavy wind damage in the core region—which goes well beyond what we’ve seen in Cat-3 landfalls—supports the conclusion that Celia was a Cat 4.

    Sources
    Monthly Weather Review – April 1971: Atlantic Hurricane Season of 1970 (R.H. Simpson & Joseph M. Pelissier)
    NHC: Preliminary Report Celia
    NOAA: Hurricane Climatology for the Atlantic and Gulf Coasts of the United States – NOAA Technical Report NWS 38 – April 1987 (Ho, Su, Hanevich, Smith, Richards)
    NWS Corpus Christi: Hurricane Celia (Tim Tinsley)
    A REANALYSIS OF THE 1944-1953 ATLANTIC HURRICANE SEASONS- THE FIRST DECADE OF AIRCRAFT RECONNAISSANCE (Andrew B. Hagen)
     
    #1 Josh Morgerman, Jan 14, 2011
    Last edited by a moderator: Jan 16, 2011
  2. My father went through this and has recounted various stories about it. Scary storm indeed.
     
  3. Josh Morgerman

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    Interesting. Was he in Corpus Christi-- or right in that area? What does he say about it? Does he remark about the wind? That was the major thing with this one.
     
  4. Dave Gallaher

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    Good analytical documentation, Josh.
     
  5. Josh Morgerman

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    Hey, thanks, Dave. :)
     
  6. He lived in a suburb close to Nueces Bay called Annaville. He was only 6 when it happened but he remarked that his roof was torn about 3/4th the way off the house. He said that 3 houses on his block were completely annihilated. He believes those were caused either by tornadoes or just a major wind tunnel effect.
     
  7. Josh Morgerman

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    Oh, yeah, Annaville is at the W end of the Bay-- at the NW end of the city-- and was in that S eyewall, where those tremendous microbursts occurred. The airport-- just ~6 mi away-- had a gust to 140 kt.

    As per the analysis above (in the first post), the damage had a streaky quality that suggested tornadoes, but careful inspection by NWS officials indicated it was all straight-line wind damage-- so that's probably what your Dad experienced.

    Thanks for sharing.
     
  8. cdcollura

    cdcollura EF5

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    Thanks for posting...

    It appears that the 1970 storm was loaded with "mini swirls" (tornado-like rotations, brief and violent, embedded in the eyewall). This is probably what caused the reinforced wall damage described.

    I have noticed that unlike northern Gulf of Mexico landfalls, storms in Texas (including Ike in 2008, and south of there), or in the FL Gulf coast south of Tampa, intensify as they make landfall (unlike in the north, where they weaken just before landfall).

    This must be the deeper heat content and / or warmer loop current.
     
  9. Josh Morgerman

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    Hey, Chris!

    Thanks for reading my analysis. I have noticed the same thing as you-- that Gulf 'canes are much more likely to be strengthening at landfall if they're not moving essentially N into the N Gulf Coast. The major 'canes that do hit from N TX to the FL Panhandle are almost always on a weakening trend. I say "almost" because there have been some important exceptions: Eloise 1975 strengthened up to landfall on the FL Panhandle, Frederic 1979 was either slowly strengthening or at least holding steady when it came ashore at the MS/AL line, and Camille 1969 was essentially holding steady when it hit MS.

    Back to Celia's winds... The peak winds definitely seem to have been spawned by some localized convective action, but-- based on the reports I've read-- they don't seem to have been caused by swirls or mesovortices. Inpectors reported that heavy debris was blasted very long distances-- in some cases over 1,000 yd-- in essentially straight lines. It seems the culprit was a cluster of microbursts that produced extremely high straight-line winds (up to EF4, according to the NWS Corpus Christi).
     
  10. Todd Counter

    Todd Counter Guest

    Texas Recorded Wind Gust Record

    I read your study and really liked it. I grew up in Portland, Texas, across the bay from Corpus. My family got home from vacationing in New Mexico the day after the storm. Needless to say, being only 4 years old at the time, the memories I have of the storm were of massive damage, people crying, heat, and mosquitos. I do remember folks talking about how it exploded just prior to landfall and the stories of damage and hard times rival those of Ike. I wanted to let you know that there is more data that may help support you Cat 4 redesigination for Celia. The record for the highest wind gust ever recorded in Texas was during Celia on 8/3/70 recorded at the US Coast Guard Station in Aransas Pass, Texas at a whopping 180 mph. Best Regards and thanks for the analysis.
     
  11. Mark McGowen

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    Thanks for the post, Josh! I used to spend hours pouring over photos and documents at the local library about Celia when I was a kid. I'm glad this Andrew-like storm is getting renewed attention. FYI: Does anyone know if the Simon & Garfunkel song came out BEFORE or AFTER this hurricane?
     

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