Tuesday, May 31, 2016

Haboob, Sandstorm, Dirt Storm? The Answer’s Blowing in the Texas Wind

By: Bob Henson , 3:02PM,GMT on May 31,2016
Just as people come to America from around the world, so do the terms we use to describe wind--although some would prefer that the nation stick to homegrown meteorological verbiage. A good case of this linguistic angst emerged on Sunday evening with the arrival of a dramatic haboob in Lubbock, TX. Rain-cooled outflow from strong thunderstorms over the Texas Panhandle pushed across the Lubbock area from the northeast, plowing up a wall of dust that was captured on video from Lubbock’s National Weather Service office (see bottom of this post). The temperature at the Lubbock NWS office dropped from 82°F at 7:03 pm CDT to 64°F at 7:10 pm CDT, with winds gusting to 56 mph and visibility down to 0.5 mile in rain and blowing dust.

Haboobs are distinct from ordinary blowing dust because of the thick dust shoveled upward--sometimes more than half a mile--by the relatively cool, dense air at the leading edge. After a haboob’s front edge moves past a given location, the airborne dust quickly abates. In contrast, blowing dust refers more generally to the situation where hours of strong wind can kick up broad areas of reduced visibility, often for hours at a time during dry, hot water. Extreme blowing dust episodes, or duststorms, typically cover a large area, as opposed to the narrow zone of a haboob. Sandstorms occur when sand grains are blown across the lowest few feet of the landscape, usually in true deserts rather than semiarid regions.


Figure 1. Intense thunderstorms located north of Lubbock at 6:15 pm CDT Sunday, May 29, 2016, pushed an outflow boundary (the faint line south of the storms) and associated haboob (not visible on radar image) toward the Lubbock area. Image credit: NWS/Lubbock.


Figure 2. Screenshot of the NWS/Lubbock Facebook entry noting that a haboob was approaching Lubbock International Airport from the north at 6:57 pm CDT Sunday, May 29, 2016. Image credit: NWS/Lubbock.


“Haboob” is derived from the Arabic word “habb” (wind), according to the AMS Glossary (American Meteorological Society). That fact has led to unrest on social media more than once over the last few years. The use of the term in media to (correctly) describe a massive haboob that plowed from southeast Arizona to Phoenix on July 18, 2011, caused enough of a local outcry to prompt an article about the controversy in the New York Times. When the NWS Lubbock office posted warnings on its Facebook page about an approaching haboob on March 11, 2014, many readers protested; when the warning was shared on a local TV station’s Facebook page, there were calls for the broadcast meteorologist to be fired. History repeated itself last Sunday when the approaching haboob was mentioned on the NWS Lubbock webpage. One commentor asked the NWS to “use the American term please.” Another said “I’ll find another weather service.”

What’s kicked up the haboob storm?
Why did it take until recently for residents of the Southwest U.S. to get excited about a once-obscure term? For one thing, intense, recurring drought over the last few years, coupled with record-warm, landscape-drying temperatures, could be making the region more prone to haboob formation at times, although this would be a difficult thing to quantify. Another factor: with their adoption of Twitter and Facebook, NWS offices now have a direct line to the public, together with the ability to introduce semi-technical terms that otherwise might not have made it through the filter of mass media. The ascent of online media has also made it more tempting for journalists and pundits to coin or promulgate terms that have a chance of going viral. Already, the age of social and online media has popularized “polar vortex,” “derecho,” and several others. It’s easy to see why a sensitized layperson might feel that certain foreign-sounding terms are being suddenly foisted on them.

Of course, there is Arabic influence throughout the world of scientific terminology. Every time you use 3, 5, or 8, you’re using an Arabic numeral. And though it’s only recently made it into public discourse, “haboob” is hardly a new term in the meteorological literature. As noted by Maryland weathercaster and AGU blogger Dan Satterfield, a 1925 paper in the Quarterly Journal of the Royal Meteorological Society was titled “Haboobs.”


Figure 3. The spectacular haboob that slammed into the Phoenix area on July 18, 2011, photographed in Maricopa. Image credit: wunderphotographer nukegm.

Other sources of wind names
Like the weather itself, weather words transcend national borders. The names we use in the United States for wind-related phenomena come from a wide array of sources. “Tornado” and “derecho” are both derived from Spanish (“thunder” and “straight,” respectively). The German-derived term “foehn wall” describes a wall of clouds that forms on the windward side of a mountain range, as seen from the leeward side; it’s often accompanied by a strong, mild “chinook” wind on the downwind side. “Chinook” is derived from the Native American term “Salishan”.

Even the all-American-sounding “downburst” and “microburst” were coined by a Japanese-American immigrant, the eminent meteorologist Theodore “Ted” Fujita (creator of the Fujita Tornado Damage Scale). First trained as a mechanical engineer, Fujita took a research flight in 1945 over the debris left by the bombs that struck Hiroshima and Nagasaki and observed starburst damage patterns emanating outward from the point of the bomb impact. Later, while surveying damage from the Super Outbreak of April 3, 1974, Fujita recognized similar starburst patterns, and he concluded that some of the damage must have resulted from descending wind bursts.

You’ll find a variety of haboob photos from around the world at the post filed by Jeff Masters on May 3, 2005. This was post #5 in this blog, out of 3317 posts to date!


Figure 4. Flooding at Lakeview Park in Humble, TX, on May 29, 2016. Image credit: wunderphotographer mcdsara1.

Continuing flood threat in southeast Texas this week
The National Hurricane Center issued its final advisory at 5:00 am EDT Tuesday on former Tropical Storm Bonnie, which had been declared post-tropical on Monday. High water resulting from more than 8 inches of rain in parts of South Carolina prompted the closure of Interstate 95 about 20 miles north of the Georgia border on Sunday, causing major traffic troubles. Flooding from a much larger area of heavy rain across Texas related to a stalled front and a slow-moving upper low has taken at least six lives since late last week. The Brazos River at Richmond, just west of Houston, was at a record-high flood stage of 53.19 feet at 7:15 am CDT Tuesday, and dozens of homes have been evacuated. More heavy rains are possible across southeast Texas later this week, which the Houston NWS office warns “will likely exacerbate flooding somewhere in our forecast area.”

Bob Henson

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