HARVEY’S A MENACE
MEMORIES OF ALLISON: Monster tropical storm that stalled, inundated the area with rain heightens worries
The first named storm of the 2001 season arrived in Houston in early June, bringing a good amount of rain but causing few problems out of the ordinary. Southeast Texas knows all about summer showers, even the heaviest ones.
But then this monster called Allison fooled everyone. Losing steam in the face of a large high pressure ridge to the north, it came to a stop and circled back on a Friday night. This time the rain would not stop.
Day after day it fell. Bayous that had not significantly left their banks in decades looked more like lakes than streams, and parts of Houston that had not flooded in living memory were awash like everyone else. Semi trucks floated like boats down flooded freeways. Twentythree people died statewide.
Now comes Harvey, which formed down south, dwindled and dawdled, then reformed with an eye on the Texas coast, quickly picking up speed. When it makes landfall late Friday night, it could be a Category 3 hurricane, the first to hit the state since Ike in 2008 and the first major storm to strike the United States in 12 years.
But people are not talking about Ike. The conversation is all about Allison,
and for one reason: stall. That lone word conjures vivid memories of the storm that decided to take up temporary residence in the greater Houston area. No one who lived through it has forgotten.
Forecasters are expecting Harvey to lose its punch quickly after hitting the sparsely populated midsection of the Texas coast. High pressure systems then could halt its forward progress, leaving it to meander to the east. Slowly.
The biggest fear is that Harvey will slow down considerably, unlike Hurricane Ike, which scored a direct hit on Houston but breezed on through. Ike’s considerable damage — the overall estimate was about $30 billion in direct losses — was caused by storm surge and wind, neither of which are anticipated to be Harvey’s main weapons. The fear is rain, buckets and buckets with only periodic relent between bands.
“Life-threatening flooding is expected across much of the Texas coast from heavy rainfall of 12 to 20 inches, with isolated amounts as high as 30 inches, from Friday through early next week,” the National Weather Service reported Thursday.
Although Houston has a long history with storms, Allison is the modern standard by which everything is measured. It brought rainfall totals between 20 and 40 inches to the greater Houston area. Photos of the aftermath remain the most powerful reminder of the vulnerability of the nation’s fourth-largest city to a mammoth rain event. So impressive was Allison’s handiwork that until 2015 it was the only tropical storm to have its name retired.
Ike was frightening in a different way. At one point it was a huge hurricane, its spiral encompassing most of the Gulf of Mexico. Because of its width and acceleration, Ike pushed water in front of it that resulted in a storm surge of about 15 feet when it hit near the east end of Galveston Island on Sept. 13, 2008.
Ike took its toll
Ike had dropped to a Category 2 hurricane at landfall, meaning sustained winds of 110 mph, less than feared a day or two earlier when comparisons to the Great Storm of 1900 abounded. Even so, the destruction was considerable. As it drove past the center of Houston, it took roofs and windows with it. Glass from downtown skyscrapers rained on the streets below. Most neighborhoods in the path soon sported plenty of blue “FEMA roofs,” so named for the brightly colored plastic tarps covering holes large and small.
Adding to the mayhem inflicted by Ike’s passage was the widespread loss of power. Some parts of town were without electricity for more than a week, even though repair crews from around the country rushed to assist.
Power is not expected to be an issue with Harvey, whose winds are not expected to cause more than minor damage in the Houston area. Current forecasts are calling for sustained winds of 25-35 mph in the Houston area, with gusts up to 45. The closer to the coast, the higher the wind speeds.
Allison was a different creature. That Friday night, June 8, saw the Texas Medical Center under water, suffering an estimated $2 billion in physical damage and the loss of thousands of laboratory animals that had been kept in basements. Likewise, downtown’s Theater District sustained water intrusion that ruined hundreds of props, costumes and priceless musical manuscripts stored in theater basements, something theater directors had never thought possible.
Allison doubled back
As Houston dried out from Allison’s first visit, a meteorological worst-case scenario caused it to stall and then double back. Rain fell for days. The final six-day official total was about 39 inches for Houston. Approximately 95,000 cars and 73,000 homes flooded, with more than 2,700 a complete loss. An estimated 30,000 people were made homeless. The tally for Texas was a bill totaling more than $5 billion, with 75 counties included in the disaster declaration of President George W. Bush.
No two storms are identical. The good news with Harvey is it appears destined to move ashore at the best possible spot, where cows greatly outnumber people. The bad is that it is expected to lose momentum between those high pressure systems.
The European medium-range forecast model, regarded by many as the most accurate in the world, projects Harvey to veer slightly east after a day or so and move out over the Gulf of Mexico and its bath-water temperatures as it ambles along the coast. One result of that could be regeneration. Think renewed vigor and more rain.
But, of course, that’s all a maybe.
Houston may be spared
“Allison is a fair comparison in one sense, but not another,” said meteorologist Eric Berger, editor of Space City Weather. “The key link between Harvey and Allison is that both systems are expected to move inland, stay relatively near the coast, and then essentially stall for a couple of days as steering currents fall apart in the upper atmosphere. This slow motion, and proximity to the warm Gulf, will allow Harvey to produce a lot of rain. Harvey has that potential, but chances are the heaviest rain will fall somewhere other than Houston just because the storm will be affecting such a wide area.”
Houston is accustomed to rain. Its streets flood by design. But there are limits. Allison was a cautionary tale of sorts. Sustained and extremely heavy rains are now beyond the region’s capacity to cope.
Increasingly volatile summer weather and the simple fact of millions of people living close to one another on a coastal plain, a large portion of it impermeable, make flooding inevitable. The Tax Day Flood of 2016, for example, showed what can happen even without a named storm or anticipated event. Eight rain gauges in Waller and western Harris counties recorded totals of more than 15 inches in one 12-hour period.