Weather Nerd

Parts of Texas "underwater," but levees spared

Hurricane Dolly was downgraded to a tropical storm late last night, and the rain and wind have finally subsided in the South Texas coastal counties where the storm dumped two feet of rain in some spots. But some areas remain “underwater” from all the flooding.

Meanwhile, in more heavily populated locales that were spared the worst of Dolly’s wrath, residents should give thanks that, thanks to a last-minute change of course, the storm’s impact wasn’t more severe.

Cameron County, the southernmost county in Texas, was hardest hit. The Brownsville Herald reports that “sheriff’s deputies and Emergency Management officials worked throughout the night rescuing residents from the Laguna Madre area from their flooded homes.” The wind damage was nothing to sneeze at, either, according to the Houston Chronicle:

The hurricane’s 100 mph winds caused extensive damage on South Padre Island, ripping the roofs off the Bahia Mar, a 10-story hotel, various condominiums and the Palmetto Inn, a two-story restaurant, as well as numerous homes in other coastal communities.

Some island residents predictably came to regret their decision to “ride it out,” according to the Chronicle. “We have a number of folks who do not wish to be on the island now,” said South Padre Mayor Bob Pinkerton. “They’ve had enough.” But, of course, Dolly closed the causeway, leaving islanders “stuck and isolated.” The time to get out was before the storm, a lesson that many coastal residents seem unable to learn the easy way.

Inland portions of Cameron County were also hit hard. “Much of the county is under water including highways and roadways,” the Brownsville Herald — which, incidentally, will be delivered today, in case you were wondering — reported this morning.

It’s easy to see why the flooding in some areas is so severe, when you look at the radar rainfall estimates. Doppler shows a miles-wide swath of land in northern Cameron County where between 20 and 25 inches of rain fell. In a few isolated spots, the estimated total exceeds 25 inches. See for yourself here, via Weather Underground:

“Surely we will be hearing of extensive damage and some fatalities, with a rain of that magnitude,” Alan Sullivan writes. But thus far, thankfully, there have been no reports of deaths or serious injuries.

As you can see on the map, the heaviest band of rain also stretches into southwestern Willacy County. The hardest-hit inland cities would appear to be Harlingen (population 66,498), the second-largest city in Cameron County (after Brownsville), and Raymondville (population 9,733), the largest city and county seat of Willacy County. Raymondville witnessed one of Dolly’s more dramatic stories, as “a crew braved gale-force winds to rescue a 10-year-old … whose ventilator stopped when the power failed,” according to the Chronicle.

Thankfully, because of a last-minute “right turn” by Dolly, the city of Brownsville (population 139,722) was spared the worst of the storm — in terms of both wind and rain — as was the more populous Hidalgo County, immediately to the west of Cameron and Willacy counties. “It didn’t dump as much as it could have,” said Kevin Pagan, director of emergency operations in McAllen, the largest city in Hidalgo County. “It’s hard to feel lucky, but it could have been worse.”

Widespread flooding along the Rio Grande appears to have been avoided, as the levees held. As the rainfall-total map shows, the river itself received “only” 8 to 12 inches of rain, while the 20+ inches that officials feared instead fell on the more sparsely populated, mostly agricultural regions to the north. “The levees are holding up just fine,” Cameron County emergency coordinator Johnny Cavazos told the AP. “There is no indication right now that they are going to crest.”

This happy eventuality should not be viewed as an indictment of the forecasts that called for the possibility of devastating floods and destructive winds in the more heavily populated areas. The National Hurricane Center’s forecasts of Dolly’s track were in fact excellent, including their emphasis on the possibility of deviations shortly before landfall due to weak steering currents. It was precisely such a deviation that took Dolly northward at the last minute, sparing Brownsville and the Rio Grande Valley a direct hit.

In any event, the forecasted 20+ inches of rain did fall, and the forecasted 90+ mph winds did occur; they just occurred a wee bit to the north. That is entirely in line with the NHC’s numerous reminders in its discussions of Dolly that we shouldn’t focus on the “center line” of the forecast track, but rather the probability “cone,” precisely due to the uncertainty of the storm’s track during its final hours before landfall.

Certainly, no one should use the good fortune of Dolly’s last-minute right-hand turn as an excuse to disregard dire warnings when future storms threaten. Mr. Pagan is right: it could easily have been much worse, and next time, it might be.

Stepping off my soapbox and getting back to the damage reports: according to the McAllen Monitor, 97 percent of households are without power in Willacy County, compared to 90 percent in Cameron County and 60 percent in Hidalgo County, as of 9:00 AM local time today. All told, about 200,000 households are in the dark, and several thousand people are staying in shelters, according to the Houston Chronicle. 9-1-1 service is offline in Cameron and Hidalgo counties. Many roads are closed or damaged. Water service has been disrupted.

There are also reports of major damage across the border in Mexico, where rain and wind were less severe, but the infrastructure is less robust.

President Bush has issued a disaster declaration for 14 counties in South Texas.

Although Dolly has weakened and moved west of the coastal regions, she continues to dump heavy rain on other parts of southern Texas and northern Mexico. The storm is expected to weaken to a tropical depression later today, and the circulation will dissipate entirely within 24 hours. Rain could continue into the weekend, however.

Here is an extensive photo gallery of Dolly’s impact on South Texas, from the Monitor.

P.S. Meteorologist and weatherblogger extraordinaire Dr. Jeff Masters and Houston Chronicle “SciGuy” Eric Berger have both posted Dolly wrap-ups. They’re both worth reading.

Dr. Masters also looks at Invest 97L, the tropical wave that I described as “proto-Edouard” over the weekend, and writes:

[The wave,] a few hundred miles west of the Cape Verde Islands, is now over cool water of 25°C. The wave still has a large circulation, but has lost all of its heavy thunderstorm activity. Until 97L can find some warmer water (which should happen by Saturday), there is little chance of it developing. Wind shear is expected to be around 15 knots on Saturday, which is marginal for development, and there is plenty of stable, dry air for it to contend with. None of the reliable computer models show development of this system.

97L came off the coast of Africa further north than expected, which has inhibited its development. The storm’s higher latitude also suggests that, if it does eventually develop, it will probably take a track more like Bertha’s than Dolly’s, and consequently is unlikely to affect the United States. That’s a very speculative assessment, though, and subject to change if the storm does develop. I’ll certainly be keeping an eye on it.

That said, it looks like we may be in for a breather on the hurricane front. Dr. Masters writes: “The four reliable computer models are not predicting development anywhere else in the Atlantic for the next 7 days.” After an exceptionally busy July to date, that would be a welcome relief.