Tornadoes and Tropical Storm in Texas, June 30, 2010

Feeder bands from Hurricane Alex began producing tropical storm force wind gusts during the very early morning of June 30th, continuing through mid evening in Coastal Cameron County. As the center of Alex neared landfall about 100 to 110 miles south of the Cameron County/Mexico border, sustained winds peaked between 39 and 51 mph, with gusts peaking between 56 and 66 mph, during the late afternoon and evening (4 to 8 PM CST). The peak sustained wind, 51 mph, was recorded at the National Ocean Service (NOS) station at the southeast tip of Port Isabel; a peak gust of 66 mph was recorded along the higher span of the Queen Isabella Bridge, with 62 mph recorded also at the NOS location and 56 mph on South Padre Island. The Automated Service Observing System station at Cameron County Airport in Bayview recorded peak sustained winds of 39 mph, with a peak gust of 53 mph at 711 PM CST. A single peak pulse gust to 51 mph was recorded at this location at 216 AM CST, from a fringe band.

No power outage estimates were available, except a quote of 1,441 in the American Electric Power (AEP) service area which includes Port Isabel. Structural damage was not significant from the tropical storm force winds alone.

A fence was reported blown in the middle of the street, and tree limbs were knocked down, behind a convenience store at the intersection of State Highway 100 and Musina Street in Port Isabel. Damage occurred within a wind speed couplet embedded within a rain band, which had a trajectory that later produced a stronger tornado in San Pedro (southwest Cameron County) about 25 minutes later. Estimated wind speed was between 50 and 55 mph.

The tornado appeared to begin near a home between Old Military Highway and Mary Lee Court, lifting a few old shingles before knocking down several large limbs in the front yard. The track continued across Old Military Highway, tipping over a water kiosk and tearing off numerous mesquite limbs before moving across Military Highway (Federal 281), where it blew down smaller mesquite trees before crossing a field and tipping over a trailer at a 45 angle onto a recreational vehicle. Damage continued into a tree stand before ending. Well built homes in the neighborhood sustained no damage; power lines remained up and power never went out as the storm raced by.

Estimated winds were 60 to 65 mph.

Cooperative observers and adjusted radar rainfall estimates suggested between 6 and 8 inches of rain fell across northeast and central Willacy County associated with feeder bands from Hurricane Alex, mostly on June 30th. As of this writing, no significant flash flooding was reported, but heavy rains caused local minor urban-type and field flooding which continued into July 1st.

Texas Military Forces reported a small, brief touch down near Highway 77 north of Raymondville. No damage was reported as of this writing.

Feeder bands from Hurricane Alex began producing tropical storm force wind gusts during the late morning and early afternoon of June 30th in Coastal Kenedy County. Outer feeder bands well ahead of the center of Alex produced sustained winds of 36 mph at Rincon del San Jose Texas Coastal Ocean Observing Network (TCOON) platform shortly after noon, with a peak gust of 47 mph at 5 PM CST (along the Laguna Madre). Stronger winds reached the Baffin Bay TCOON platform (3 to 4 miles north of the Kenedy County shoreline) by late afternoon, with sustained winds reaching 41 mph with a gust to 64 mph a little after 4 PM.

Sustained winds were below tropical storm strength over inland Kenedy County, interpolated from the nearby Kingsville Naval Air Station in Kleberg County, just 20 miles north.

Increasing and persistent east to northeast flow built seas above 22 feet east of the Lower Texas coast on June 30th with a swell period of more than 12 seconds brought a minor to moderate storm surge to South Padre Island and neighboring communities along Laguna Madre Bay, including Port Isabel, Laguna Heights, and Laguna Vista. Peak surge reached 3.52 feet (4.19 total tide MLLW) at the Port Isabel tide station at 630 CST; a 3.44 foot surge (3.95 total tide MLLW) was recorded on the other side of the bay at the South Padre Island Coast Guard Station.

On South Padre Island, the building waves pushed water through public beach access points 4 through 6 north of the resort area, temporarily closing State Highway 100 in these areas. Water reached into the dunes but did not breach them completely; beach surf was reported at 7 to 9 feet with very rough and confused waves. The event and impact on the beach was similar to that from Gustav on Labor Day (September 1) 2008; erosion was minor to moderate and the beach recovered quickly.

In Port Isabel, reports and visual evidence showed flooded streets and water around raised homes in prone-areas, particularly along and near Island Avenue. Only minor damage was reported in these areas.

More than 6 inches of nearly steady rain in less than 12 hours created poor drainage and flash flood conditions in the Town of South Padre Island, where main and secondary roads became impassible for a period of time during the afternoon of June 30th. While water lapped at structures along Padre Boulevard (Highway 100), no significant damage was reported from the freshwater rainfall as of this writing.

Feeder bands from Hurricane Alex began producing tropical storm force wind gusts during the late morning and early afternoon of June 30th in Coastal Willacy County. Outer feeder bands well ahead of the center of Alex produced sustained winds of 45 mph near Arroyo City (Cameron County, just south of the Willacy line) at 142 PM CST; a peak gust of 64 mph occurred in a outer band thunderstorm cell at 912 AM CST. Gusts reached 47 mph at 5 PM CST at Rincon del San Jose (in the Laguna Madre of Kenedy County); interpolating between the two locations supports occasional sustained winds near Port Mansfield and other locations toward the coast of Willacy County.

No power outage estimates were available for the area, and there were no known reports of structural damage in Port Mansfield.

Widespread urban flooding affected an area from west of Brownsville through Brownsville, Olmito, Los Fresnos, and near Bayview during the afternoon and into the overnight hours of June 30th and into July 1st (see July report for continuation of event). Much of the flash flooding, where water reached 3 feet or higher or threatened structures, occurred in typically poor drainage locations in all areas.

Total rainfall for the entire event ranged from 8 to near 10 inches in the areas that tended to flood, with an estimated 5 to 7 inches occurring during and just prior to the significant flood impacts. Damage from freshwater flooding directly due to Alex was unknown as of this writing; a best estimate is provided.

Feeder bands from Hurricane Alex began producing tropical storm force wind gusts during the late morning and early afternoon of June 30th in Cameron County. As the center of Alex neared landfall about 100 to 110 miles south of the Cameron County/Mexico border, sustained winds peaked between 38 and 40 mph, with gusts peaking between 45 and 50 mph, during the late afternoon and evening (4 to 8 PM CST).

The strong and sometimes persistent winds briefly knocked out power to at least 8,000 City of Brownsville (and nearby communities) customers, and hundreds of tree limbs were blown down, many of them small to medium sized. Minimal property damage was noted from the winds as of this writing, but did include a fireworks stand turned over, a fence blown down, and a car moved across the road by a pulse gust associated with a feeder band at 1130 AM CST along Wilson Road in Harlingen. There was no confirmation of a tornado with this report, but several funnel clouds were reported by the public at various times during the afternoon, including near La Feria (1225 PM CST), the Harlingen/Valley Airport (158 PM CST), 346 PM CST near Santa Rosa, and 6 PM CST in Brownsville.

Widespread urban and poor drainage flooding affected an area from Mercedes and Weslaco northwest to Edinburg, likely including known flood problem areas in Elsa, Edcouch, La Villa, and other places where drainage remained an issue nearly two years after Dolly. The flooding began toward sunset after more persistent heavy rains arrived in the area, and continued beyond the end of June and into July (see July report for additional times). Much of the flash flooding, where water reached 3 feet or higher or threatened structures, occurred in these typically poor drainage locations in all areas.

Total rainfall for the entire event ranged from 8 to near 10 inches in the areas that tended to flood, with an estimated 4 to 7 inches occurring during and just prior to the significant flood impacts. Damage from freshwater flooding directly due to Alex was unknown as of this writing; a best estimate is provided.

Crop damage, specifically sorghum (irrigated/dryland) losses, due to the widespread heavy rains affecting the crop at a key growing period at more than 1800 locations, approached $10 million.