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Posts Tagged ‘Santorini

“You have to be in the right place at the right time. Or the wrong place at the wrong time, depending on your perspective”*…

 

Hailstones

 

Hailstones are balls (or spikes, or flattish pancakes) of frozen precipitation that measure at least 0.2 inches across, according to the National Oceanic and Atmospheric Administration’s Severe Storms Laboratory. Several other types of smaller frozen precipitation are known as “ice pellets,” reports the National Snow & Ice Data Center, and may take the form of graupel (soft balls of water droplets clinging to a snow crystal and looking like Styrofoam) or sleet (essentially icy raindrops). In the sky, either of these can serve as an “embryo,” the little nucleus around which a hailstone can grow. The longer a fledgling hailstone stays lofted in a thunderstorm’s fierce updraft, the bigger it gets. Beyond that minimum 0.2-inch threshold, there are a few finer distinctions between hailstones, thrown around by researchers and sometimes forecasters at the National Weather Service. “Severe” hail has a maximum dimension of one inch or more, “significantly severe” stones are larger than two inches, and “giant” hail is bigger than four inches.

“Giant” sounds pretty big, but this crop of researchers didn’t think it seemed quite big enough. A hailstone of more than four inches is “certainly very large,” says Matthew Kumjian, a meteorologist at Penn State University and lead author of the paper. But, he adds, while stones of that size are rare, “they are not exceptional.” Hailstones bigger than four inches are reported 30 to 40 times a year in the United States alone, he says. Stones larger than six inches, though, are few and far between. Kumjian’s co-author, graduate student Rachel Gutierrez, combed through reports and found about 10 confirmed instances in the last 10 or 15 years, mostly in the U.S. (There were a handful of unconfirmed reports in Australia, Africa, and Asia, but photos or official measurements were missing.)

The researchers suspect that there are probably more of these spectacularly sized hailstones dropping down across the country, but they’re likely going unnoticed. When measuring hail, time is of the essence: Hailstones vanish fairly quickly, especially in hot or humid conditions, or if they shatter on impact; even large ones with cushioned falls might be overlooked. The most severe hailstorms in the United States are in the Great Plains, Kumjian says, where people are spread fairly far apart…

They’re huge; they’re rare; and they’re melting all the time: “The Slippery Problem of Measuring Enormous Hunks of Hail.”

* Matthew Kumjian, a meteorologist at Penn State University, on measuring hailstones

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As we check the weather, we might recall that it was on this date in 1883 that the volcano on the Indonesian island of Krakatoa began to release huge plumes of steam and ash. Roughly three months later, on August 27, it erupted in earnest– with a sound so loud that it circled the earth four times.  (As big as the explosion was, it was not the biggest in history: experts suggest that Santorini’s eruption in 1628 BCE was three times as powerful.)

300px-Krakatoa_eruption_lithograph source

 

Written by LW

May 20, 2020 at 1:01 am

So graphic!…

Long-time readers know that your correspondent is a sucker for nifty charts, elegant tables, and incisive visual displays of all sorts.  In the spirit of earlier-featured Jessica Hagy/Indexed and Gary Damrauer/New Math, a pointer to GraphJam, where one will find illustrated insights like:

More here.

As we attempt to keep X and Y straight in our minds, we might shudder to recall that it was on this date in 1883 that the volcano at Krakatoa (Krakatau) erupted with full force.  The sound was heard over 2,000 miles away (that’s over 7.5% of the earth’s surface– the equivalent of an explosion in New York City being heard in San Francisco); tsunamis caused by the great blast killed 36,000 people in Java and Sumatra.

But there was another sense in which Krakatoa was importantly “the sound heard ’round the world”:  While news of Lincoln’s assassination (only 18 years earlier) had taken almost two weeks to reach London,  Europe and the U.S. knew of Krakatoa in about four hours.  In the years between 1865 and 1883, there had been three interrelated developments: the global spread of the telegraph, the invention of Morse Code, and the establishment of Reuter’s news agency… and the world had become much smaller.  (C.F., Tom Standage’s marvelous The Victorian Internet for the details– both remarkable and altogether resonant with today.)

(As big as the explosion was, it was not the biggest in history: experts suggest that Santorini’s eruption in 1628 BCE was three times as powerful.)

An early 19th-century illustration of Krakatoa

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Written by LW

August 26, 2009 at 12:01 am

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