Storm Surge/Tide — Coastal Kenedy County, Texas

2020-10-08 to 2020-10-09 · Coastal Kenedy County, Texas

Event narrative

The passage of Hurricane Delta about 200 to 225 miles east of the Kenedy County coast around 4 AM on October 9th produced estimated peak sea heights of 35 feet just prior to the eye's arrival at 1140 PM CDT on the 8th. Swell periods of more than 12 seconds began during the late afternoon at the site, and propagated quickly to the Kenedy County barrier island. Soon after the time of high tide (likely between 2:30 and 3:30 AM), the combination of strong wave push with these above predicted tides likely produced significant beach erosion on the beach-facing barrier island.

Wider weather episode

As Hurricane Delta moved northward across the Gulf of Mexico in early October, outgoing swell propagated into the lower Texas coastal waters on October 8th through the 10th. This swell was powerful enough to push water into the dunes across South Padre Island around high tide, which occurred at 12:11 AM CDT on the 8th, 1:15 AM CDT on the 9th, and 2:08 AM CDT on the 10th. The most significant erosion and overwash occurred during the pre-dawn hours of October 9th, as Delta passed directly over a NOAA buoy around 200 miles east of South Padre Island at around 1150 PM on October 8th. However, the highest *tide* level that was reported was 2.38 feet above Mean Higher-High Water (MHHW; or the level above normally dry ground at the shoreline) a day later at 3:42 AM CDT on the 10th. Levels remained above 1.25 feet MHHW for several hours surrounding the occurrence of high tide on the evenings of October 7th through the 10th. This activity was enough to cause some coastal erosion, with the more significant flooding and erosion occurring on the 9th, with additional run-up and lighter erosion on the 10th.

Farther up the coast, similar wave action and minor coastal flooding was likely - but there were no comparative measurements based on MHHW.

Source: NOAA Storm Events Database, event_id 925731. Narrative written by the NWS forecast office that issued the report.