Planetary, synoptic, meso-alpha, meso-beta, local, and more—there are atmospheric scales aplenty discussed at AMS meetings. Enter microtopography, a once-rare word increasingly appearing in the mix in research (for example, here and here).
The word is also coming up as researchers are getting new tools to examine the interaction of tornadoes with their immediate surroundings. Microtopography looks like a potential factor in tornadic damage and in the tornadoes themselves, according to an AMS Annual Meeting presentation by Melissa Wagner (Arizona State Univ.) and Robert Doe (Univ. of Liverpool), who are working on this research with Aaron Johnson (National Weather Service) and Randy Cerveny (Arizona State Univ). Their findings relate tornado damage imagery to small changes in local topography thanks to the use of unmanned aerial systems (UASs).
Microtopographic interactions of tornadic winds were captured in their UAS imagery. Here’s the 5-meter resolution RapidEye satellite imaging of a 30 April 2017 Canton, Texas, tornado path (panel a) versus higher-resolution UAS imaging:
The UAS surveys show that tornadic winds interact with sunken gullies, which appear as unscarred, green breaks (circled in red) in the track of browned damaged vegetation:
Erosion and scour are limited within the depressed surfaces of the gullies compared to either side. In another section of the track, track width increases with an elevation gain of approximately 74 feet, as shown in a digital elevation model and 2.5 cm resolution UAS imagery:
The advent of unmanned aerial vehicles (UAVs) has opened new windows on tornado damage tracks. Decades ago, damage surveys took a big leap forward with airplane-based photography that provided a perspective difficult to achieve on the ground. Satellites also can provide a rapid overview but in relatively low resolution. UASs fly at 400 feet—and are still limited to line-of-sight control and the logistics of coordinating with local emergency and relief efforts, regulatory and legal limitations, not to mention still-improving battery technology.
However, UASs provide a stable, reliable aerial platform that benefits from high-resolution imaging and can discern features on the order of centimeters across. Wagner and colleagues were using three vehicles with a combined multispectral imaging capability that is especially useful in detecting changes in the health of vegetation. As a result their methods are being tested primarily in rural, often inaccessible areas of damage.
UAS technologies thus can capture evidence of multi-vortex tornadoes in undeveloped or otherwise remote, vegetated land. The image below shows a swath with enhanced surface scour over two hills (marked X). The arrow on the right identifies speckled white surface erosion, part of the main tornado wedge. Such imagery explains why, among other research purposes, Wagner and Doe are developing the use of UASs in defining tracks and refining intensity-scale estimates.
History
Eight Decades: Mapping New England Catastrophe
Eighty years ago today (September 21st), the Great New England Hurricane of 1938 ripped across New York’s Long Island and slammed into the Northeast, killing more than 600 people and clawing its way across New England and the record books. Every hurricane to strike the region since is compared to this behemoth, and none has come close to its devastating intensity.
Ferocious winds gusting beyond category 5 intensity and an enormous storm surge that wiped out coastal Long Island and flooded into Rhode Island and Connecticut were its hallmarks. Copious rains also brought by the hurricane fell on soils swamped by heavy rain just days before the storm, leading to widespread flooding and thousands of landslides. Eight decades. And its imprint is still being realized.
Recently, new precipitation data on the storm and a precursor heavy rain event—now understood to be ubiquitous before New England hurricanes—were found. This precipitation map (right) newly appears in the 2nd edition of Taken by Storm 1938: a comprehensive social and meteorological history of the Great New England Hurricane, by Lourdes B. Avilés, professor of meteorology at Plymouth State University.
(U.S. Geological Survey)
The map was created by a grad student Avilés was advising—Lauren Carter—who painstakingly digitized thousands of observations from more than 700 daily weather stations Avilés had unearthed, spanning the 6-day event. This unique updated rainfall map is just one of many new and interesting finds detailed in the new edition of her book, which is now available in the AMS Bookstore. The book’s website houses supplemental information, including more color rainfall maps, detailed reports, and photos.
1871 Hawaii Hurricane Strike Shows Lane's Imminent Danger Isn't Unprecedented
Powerful Hurricane Lane is forecast to skirt if not directly hit Hawaii as a slowly weakening major hurricane today and Friday. Its track is unusual: most Central Pacific hurricanes either steer well south of the tropical paradise or fall apart upon approaching the islands. But a recent paper in the Bulletin of the AMS reveals that such intense tropical cyclones menace Hawaii more frequently than previously thought.
Hurricane Lane as of Thursday morning local time was packing sustained winds of 130 mph with gusts topping 160. Its expected track (below) is northward toward the middle islands today and early tomorrow, followed by a sharp left turn later Friday. When that left hook occurs will determine the severity of the impacts on Maui as well as Oahu, home to Hawaii’s capital and largest city, Honolulu. Although Lane is expected to slowly weaken due to increasing wind shear aloft, it appears that the Big Island of Hawaii, Maui, Molokai, and Oahu will be raked at a minimum by tropical storm winds gusting 55-70 mph, pounding surf, and heavy, potentially flooding rain. Hurricane conditions on these islands also are possible.
The last major hurricane to affect the islands with more than swells and heavy surf was Hurricane Iniki in 1992. It was passing well south of the islands when an approaching upper-air trough brought in steering flow out of the south, and Iniki made a right turn toward the western islands while intensifying into a strong Category 4 hurricane. It slammed directly into the garden island of Kauai with average winds of 145 mph and extreme gusts that damaged or destroyed more than 90 percent of the homes and buildings on the island. Iniki obliterated Kauai’s lush landscape, seen in its full splendor in such movies as Jurassic Park, which was filming there as the storm bore down.
The only other known direct hit on Hawaii was by 1959’s Hurricane Dot, which was a minimal Category 1 storm–the winds barely reaching threshold hurricane intensity of 74 mph when its center crossed Kauai. Without any prior record of major hurricane landfall, Iniki was not just rare, it was considered unprecedented.
Until now.
More than a century before Iniki, a major hurricane crashed into the Big Island, its intense right-front quadrant passing directly over neighboring Maui, causing widespread devastation on both islands. Its discovery is outlined in Hurricane with a History: Hawaiian Newspapers Illuminate an 1871 Storm, which details the narrative thanks to an explosion of literacy on the islands in the mid 19th century, which led to hundreds of local language newspapers that published eyewitness accounts of the storm.
The new historical research, published in the January 2018 BAMS, found unequivocal evidence of an intense hurricane that struck August 9, 1871, causing widespread destruction from Hilo on the eastern side of the Big Island to Lahaina on Maui’s west side. A Hawaiian-language newspaper archive of more than 125,000 pages digitized and now made publicly available along with translated articles contained account after account of incredible damage that led the paper’s authors to surmise that at least a Category 3 if not a Category 4 hurricane hit that day.
The paper’s analysis is put forth as “the first to rely on the written record from an indigenous people” of storms, droughts, volcanic eruptions, and other extreme natural events. Accounts published in Hawaiian newspapers create a living history of the 1871 hurricane’s devastation, as recounted in the paper:
“On the island of Hawaii, the hurricane first struck the Hāmākua coast and Waipi‘o valley. The following is from a reader’s letter from Waipi‘o dated 16 August 1871:”
At about 7 or 8 AM it commenced to blow and it lasted for about an hour and a half, blowing right up the valley. There were 28 houses blown clean away and many more partially destroyed. There is hardly a tree or bush of any kind standing in the valley (Pacific Commercial Advertiser on 19 August 1871).
“An eyewitness from Kohala on Hawaii Island wrote the following:”
The greatest fury was say from 9 to 9:30 or 9:45, torrents of rain came with it. The district is swept as with the besom of destruction. About 150 houses were blown down. A mango tree was snapped as a pipe stem, just above the surface of the ground. Old solid Kukui trees, which had stood the storms of a score of years were torn up and pitched about like chaff. Dr. Wright’s mill and sugarhouse, the trash and manager’s residence, were all strewn over the ground (Ke Au Okoa on 24 August 1871).
“On Maui, newspaper reports document that Hāna, Wailuku, and Lahaina were particularly hard-hit. A writer in Hāna described the storm:”
Then the strong, fierce presence of the wind and rain finally came, and the simple Hawaiian houses and the wooden houses of the residents here in Hāna were knocked down. They were overturned and moved by the strength of that which hears not when spoken to (Ka Nupepa Kuokoa on 26 August 1871).
“In Wailuku the bridge was destroyed:”
… the bridge turned like a ship overturned by the carpenters, and it was like a mast-less ship on an unlucky sail.” (Ka Nupepa Kuokoa on 19 August 1871).
“From Lahaina came the following report:”
It commenced lightly on Tuesday night, with a gentle breeze, up to daylight on Wednesday, when the rain began to pour in proportion, from the westward, veering round to all points, becoming a perfect hurricane, thrashing and crashing among the trees and shrubbery, while the streams and fishponds overflowed and the land was flooded (Pacific Commercial Advertiser on 19 August 1871).
The BAMS paper concludes that the 1871 hurricane was “a compact storm, similar to Iniki.” Honolulu escaped damaging winds or rain despite such a close encounter.
Because such historical records have been unnoticed for so long, the paper notes “a number of myths have arisen such as ‘the volcanoes protect us,’ ‘only Kauai gets hit,’ or ‘there is no Hawaiian word for hurricane.’”
Today’s powerful Hurricane Lane and the newfound historical records go a long way to dispelling these misconceptions about the threat of hurricanes in the Hawaiian Islands.
Epic Blizzards Paralyzed New England, Midwest 40 Years Ago
By Chris Cappella, AMS
It began with a whisper. And ended in smothered silence for millions.
Slideshow of blizzard photos.
I’ll never forget seeing tiny snowflakes blowing down Ocean Avenue in our small sea-side suburb of New Haven. In my hometown of West Haven, on the south shore of central Connecticut overlooking Long Island Sound, when snow fell it usually just stuck, firmly. On everything. The relative warm ocean water often changes our winter events to miserably cold rain. It never allows for dry, powdery snow. Or so I thought. Today—February 6, 1978—would be different. Far, far different. Than many of us hearty New Englanders, as we’re known, had ever seen. For that silky soft sinewy snow I was seeing in the infancy of this storm would grow into a furious blizzard and bury the region—a blizzard by which all others there since would be measured.
The tiny flakes blew into snowy tendrils that would side-wind down the road until they escaped the wind. And pile into miniature snowdrifts. A harbinger of things to come, but on a gigantic scale. This was the beginning of the epic Blizzard of ’78 in New England. Over the next 30+ hours, the snow would fall heavier than anything I—and most of us in the Northeast—had ever experienced. Sideways snow. Two to three inches an hour. For hours and hours. Blowing in winds gusting over 50 mph region-wide, and to hurricane force along the coast. 110 mph Scituate, Massachusetts. Snow so deep even as a 12-year-old I would struggle to walk in it. Drifts so large and deep they dwarfed entire houses. You could jump off second-story rooftops into them. And my friends and I did. Off our grammar school roof. Even its 45-foot high gymnasium roof. Weightless, for a second or two. And then: whump! We’d completely disappear in snowdrifts 10-15 feet tall.
Buried barely begins to describe the otherworldly landscape. Nearly all human life in the region would slow down and eventually grind to a halt. Thousands of people stranded on roadways as blinding snow enveloped everything, too quickly to make an escape. Governor Ella T. Grasso ordered all vehicles off the roads. We capitalized on it. Building giant snow forts with tunnels in the mountains of snow piled on sides of our road. Only once, though, did we recklessly dive into our snow tunnels to escape an oncoming snowplow. Luckily for us kids the snowplow only took out the last 3-4 feet of our tunnels, sparing us certain death. By snowplow.
Legendary Boston meteorologist, Harvey Leonard, who was just 29 then, remembers seeing “big potential” for a major snowstorm coming together in the Northeast four days beforehand—a lead-time “close to unheard of” in those days, he told The Boston Globe in a recent article chronicling the blizzard.
“As a person — not only a meteorologist, but somebody who really loves weather and is fascinated by storms, particularly winter storms — it was pretty amazing to see what was unfolding. ‘78 still stands as the most powerful and wide-reaching storm that I’ve ever been involved in forecasting and experiencing.”
The defacto “official” website devoted to the storm—blizzardof78.org—put together by amateur historian Matt Bowling describes how a failed forecast weeks earlier set up a situation in which people headed to work and school that Monday morning, February 6, as if just a routine snowfall was expected.
It is safe to say that by the time February 6th, 1978 came along, New Englanders had been pretty-well trained to not pay much attention to the weathermen. It had been a difficult winter already. On January 21st, as most forecasters predicted only rain, New England had been blanketed by a major league snowstorm that dropped 21 inches of snow in Massachusetts and downed a record number of power lines in Rhode Island. This forerunner to the Blizzard of ’78 had brought so much snow that the roof of the Hartford Civic Center actually collapsed from the weight. When forecasters began predicting another big storm, nobody thought too much of it.
In a series of quotes gathered and posted to the site, WTNH-TV meteorologist and Western Connecticut State University professor Dr. Mel Goldstein continues this theme, describing why there was skepticism about the forecast for the storm:
Back in 1978 we did not have the accuracy of the computer models that we have today. And in 1978 there was a brand new computer model that came out and it was predicting the storm to be pretty much the magnitude it turned out to be. But because the computer model was brand new, people did not have confidence in it. And so there was some question whether or not people wanted to buy into the kind of product that it was delivering. To me it looked very reasonable … and I took my little bag of clothes and I moved into Western Connecticut State College weather lab and I said, ‘I’m going to be here for a few days and there’s no question about that. It’s in the logbook on that day: ‘a granddaddy of a snowstorm is coming our way.’
And in another Boston Globe article, noted weather columnist David Epstein wrote four years earlier about The meteorology behind the blizzard of February 6-7th 1978. In his article he reiterates how so many were caught off guard by the blizzard.
Computer models were still relatively new and a series of busted forecasts left many people skeptical that a big storm was actually coming. On the morning of the 6th, snow was suppose to start prior to the morning commute. However, when folks awoke and saw the snow hadn’t begun many of them decided it was another busted forecast and went to work. These same people would then try to get home that afternoon while the blizzard was fully underway.
A search on YouTube turns up numerous documentaries on the Blizzard of ’78, including “Blizzard of ’78,” below, on Leonard’s station WCVB.
Remarkably, New England’s Blizzard of ’78—with its record snowfall observations in Boston and Providence and its utter destruction along the Massachusetts coast as powerful winds slammed monster waves ashore through four tide cycles—came on the heels of a nearly equally intense blizzard that slammed the Midwest on January 25-27. That Blizzard of ’78 became known as the White Hurricane, with wind gusts of 100 mph and feet of snow shutting down states from Wisconsin to Ohio. It set pressure records (956.0 mb in Mount Clemens, Michigan—third lowest non-tropical atmospheric pressure ever recorded in the Unites States) and remains the worst blizzard on record in Ohio, Indiana, and Michigan.
Its magnitude was summed up in a statement by NWS Detroit meteorologist C. R. Snider on January 30, 1978:
The most extensive and very nearly the most severe blizzard in Michigan history raged January 26, 1978 and into part of Friday January 27. About 20 people died as a direct or indirect result of the storm, most due to heart attacks or traffic accidents. At least one person died of exposure in a stranded automobile. Many were hospitalized for exposure, mostly from homes that lost power and heat. About 100,000 cars were abandoned on Michigan highways, most of them in the southeast part of the state.
Nearly three dozen times as many cars abandoned—and that was in just one Midwestern state.
To some, Blizzard of ’78 conjures up memories of a similar yet completely different storm.