May 2021 South Central United States flooding

May 2021 South Central United States flooding
The weather system partially responsible for the May 2021 South Central United States flooding, entering the Gulf of Mexico on May 19
DateMay 16, 2021 (2021-05-16)–late May 2021[1]
LocationMost of the South Central United States
Deaths5[2]
Property damage$1.1 billion[3]

In May 2021, prolonged rainfall from a series of weather disturbances affected the South Central United States, namely Texas and Louisiana.[4] As a result of rainfall totals, which peaked at 17.16 in (43.6 cm) in Fannett, Texas, widespread flash flooding occurred.[1] Outside those states, Kansas saw up to 8.16 inches (20.7 cm) of rain, and 70 miles per hour (110 km/h) wind gusts, while New Mexico recorded a 69 miles per hour (111 km/h) wind gust.[5]

Meteorological history[edit]

At around 18:00 UTC on May 16, 2021, an outflow boundary developed over Northeastern Texas and moved generally southward.[6][7] The outflow boundary then dissipated just 12 hours later and was quickly followed by an outbreak of severe thunderstorms over Texas while torrential rainfall began to affect portions Louisiana and Southeastern Texas. As a result of this rainfall, flash flooding began to occur over southeastern Texas and southwestern Louisiana.[8][9] Throughout the day, several areas of low pressure and outflow boundaries developed over the Texas Hill Country.[10][11] This caused severe thunderstorms to form over the region, which brought gusty winds, rainfall, and even some reports of hail.[12] The next day, showers and thunderstorms began to develop over South Texas, which brought further rainfall to the area.[13] On May 19, another round of severe thunderstorms moved through both Texas and Louisiana, worsening flooding across both states, and even causing impacts as far away as Oklahoma, Arkansas, and Mississippi.[14]

These storms exited into the Gulf of Mexico, and began to be monitored by the National Hurricane Center (NHC) on May 21 for potential tropical cyclogenesis. Initially only given a low chance to develop, the NHC did note that conditions were slightly favorable for a short-lived tropical depression or storm to form in the western Gulf of Mexico, before the disturbance moved ashore back into Texas.[15] By 12:00 UTC that day, a low-level circulation formed in association with the disturbance, however, the system lacked convection needed to designated as a tropical cyclone.[16] Winds near the center reached up to 35 mph (56 km/h), with the NHC stating that any increase in thunderstorm activity would warrant the upgrade to a tropical depression, with the chance of doing so being raised to about 60%.[17] Although at 0:00 UTC on May 22 while the disturbance was located roughly 150 mi (240 km) east-southeast of Corpus Christi, Texas, the probability of tropical cyclogenesis was lowered to around 50%.[18] Had the system developed into a tropical storm, it would have either received the name Ana or Bill, if the former had not been taken by another more-organized disturbance near Bermuda.[19]

Effects[edit]

Texas[edit]

A snapped tree at the National Weather Service Office in Corpus Christi following a severe thunderstorm on May 19

Ahead of the severe weather outbreaks in Texas, flash flood alerts were put in place across Texas, which affected millions of residents.[20]

In Portland, the Green Lake Dam collapsed following heavy rains at the Northshore Country Club.[21] Oer 100,000 residents of Texas lost power.[22] Wind gusts soared up to 71 miles per hour (114 km/h) in Dimmitt, Texas, while hail in Snyder, Texas reached 4.25 inches (10.8 cm) of rain.[5] Several cities in Texas broke rainfall records May 19 with 2–3 inches (5.1–7.6 cm) of rain.[23] Parts of Jefferson County, Texas were put under a flash flood emergency, which also extended into Louisiana.[24]

Louisiana[edit]

All five deaths occurred in Louisiana, four due to driving in flooded waters, according to John Bel Edwards.[25] In Lake Charles, Louisiana, a 24-hour period saw 11.8 inches (30 cm) of rain, a daily record.[26]

References[edit]

  1. ^ a b Matthew Cappucci (May 19, 2021). "Serious flood threat continues in Texas, Louisiana as more heavy rain brews". The Washington Post. Retrieved May 22, 2021.
  2. ^ "Heavy Rain may bring more floods to Louisiana, Texas; 5 dead". Reuters. May 21, 2021. Retrieved May 22, 2021.
  3. ^ Global Catastrophe Recap - May 2021, Aon, June 2021
  4. ^ "South inundated after torrential rain sparks flooding". The Mercury News. CNN.Com Wire Service. May 18, 2021. Retrieved May 22, 2021.
  5. ^ a b Travis, Courtney (May 16, 2021). "Texas, Louisiana at risk for major flooding". Retrieved May 8, 2022.
  6. ^ "WPC Surface Analysis Archive". Weather Prediction Center. May 16, 2021. Retrieved May 22, 2021.
  7. ^ "WPC Surface Analysis Archive". Weather Prediction Center. May 16, 2021. Retrieved May 22, 2021.
  8. ^ "WPC Surface Analysis Archive". Weather Prediction Center. May 17, 2021. Retrieved May 22, 2021.
  9. ^ Jackson Dill, Jennifer Gray (May 17, 2021). "Baseball-sized hail threatens again as flood risk increases". CNN. Retrieved May 22, 2021.
  10. ^ "WPC Surface Analysis Archive". Weather Prediction Center. May 17, 2021. Retrieved May 22, 2021.
  11. ^ "WPC Surface Analysis Archive". Weather Prediction Center. May 17, 2021. Retrieved May 22, 2021.
  12. ^ Russell Falcon, Wes Wilson (May 17, 2021). "GALLERY: Severe storms move across Central Texas Monday afternoon". KXAN. Retrieved May 22, 2021.
  13. ^ Juan Acuña (May 18, 2021). "Flash Flood Watch issued for South Texas". KRIS. Retrieved May 22, 2021.
  14. ^ Aya Elamroussi (May 19, 2021). "Millions in Texas and Louisiana are under flash flood watches due to torrential rain". CNN. Retrieved May 22, 2021.
  15. ^ Daniel Brown, Andrew Latto (May 21, 2021). "Two-Day Graphical Tropical Weather Outlook". National Hurricane Center. Retrieved May 22, 2021.
  16. ^ Jack Beven, Philippe Papin (May 21, 2021). "Two-Day Graphical Tropical Weather Outlook". National Hurricane Center.
  17. ^ Jack Beven, Philippe Papin (May 21, 2021). "Two-Day Graphical Tropical Weather Outlook". National Hurricane Center. Retrieved May 22, 2021.
  18. ^ Daniel Brown, Andrew Latto (May 22, 2021). "Two-Day Graphical Tropical Weather Outlook". National Hurricane Center. Retrieved May 22, 2021.
  19. ^ "Hurricane season could get an early start if Ana and Bill strengthen". Tampa Bay Times. Retrieved May 22, 2021.
  20. ^ "Millions across southeast Texas and part of Louisiana remain under flash flood watches into Thursday". Crossroads Today. CNN. Retrieved May 22, 2021.
  21. ^ "Green Lake Dam collapses in Portland following severe weather". Microsoft News. KRIS. May 19, 2021. Retrieved May 22, 2021.
  22. ^ Elamroussi, Aya (May 19, 2021). "Millions in Texas and Louisiana are under flash flood watches due to torrential rain". CNN. Retrieved May 8, 2022.
  23. ^ Record Rainfall for the Mid Valley, Valley Central, May 19, 2021
  24. ^ Flooding Emergencies Declared in Louisiana, Texas; Widespread Flooding Reported in Baton Rouge, The Weather Channel, May 18, 2021
  25. ^ "Heavy rain may bring more floods to Louisiana, Texas; 5 dead". Reuturs. Retrieved May 8, 2022.
  26. ^ "Severe storms lash Texas and Louisiana, flood emergency declared". The Watchers. May 18, 2021. Retrieved May 8, 2022.
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