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A Rare East Coast Tsunami

NOAA
NOAA

The derecho (fast-moving band of severe thunderstorms) that clobbered the Northeast on June 13 was nothing terribly special by National Weather Service standards; meteorologists classified it as “low-end.” But the storm’s aftereffects—kicking up six-foot waves in more than 30 tidal gauges along the East Coast—spurred a more elusive natural phenomenon: a tsunami.

Well, maybe not exactly a tsunami. Paul Whitmore, director of the National Oceanic and Atmospheric Administration Center For Tsunami Research, explained that the wave was probably just a “meteotsunami”—caused by meteorological conditions, not seismic activity. The derecho system that moved through the Northeast might have changed the air pressure just enough to “generate waves that act like tsunamis,” Whitmore said.

The tsunami’s cause is still under review: the West Coast and Alaska Tsunami Warning Center says it could be anything from the strong storm to the continental shelf east of New Jersey slumping. Typically in tsunamis, water moves out to sea and rapidly rushes back in, but water speeds reported in Rhode Island indicated something other than a storm surge.

The tsunami (for now) wave peaked at just under a foot above sea level at a tide gauge in Newport, Rhode Island, and NOAA tracked the tsunami signal from Massachussets down to North Carolina; reports came in from as far as Puerto Rico and the Bahamas. An eyewitness account from a spear fisherman on the Jersey Shore, Brian Coen, noted an approximately 6-foot wave exposing rocks that were typically submerged in three or four feet of water.

True tsunamis, Japanese for “harbor wave,” are generated by sudden shifts in the seafloor, landslides, or volcanic activity. The last significant meteotsunamis to hit the East Coast occurred in 1992 in Daytona Beach, Florida and 2008 in Boothbay Harbor, Maine. There’s dispute whether an East Coast derecho at the end of June in 2012 stirred up a meteotsunami in the Chesapeake Bay—waves reportedly only reached 40 centimeters.

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History
The Queen of Code: Remembering Grace Hopper
By Lynn Gilbert, CC BY-SA 4.0, Wikimedia Commons

Grace Hopper was a computing pioneer. She coined the term "computer bug" after finding a moth stuck inside Harvard's Mark II computer in 1947 (which in turn led to the term "debug," meaning solving problems in computer code). She did the foundational work that led to the COBOL programming language, used in mission-critical computing systems for decades (including today). She worked in World War II using very early computers to help end the war. When she retired from the U.S. Navy at age 79, she was the oldest active-duty commissioned officer in the service. Hopper, who was born on this day in 1906, is a hero of computing and a brilliant role model, but not many people know her story.

In this short documentary from FiveThirtyEight, directed by Gillian Jacobs, we learned about Grace Hopper from several biographers, archival photographs, and footage of her speaking in her later years. If you've never heard of Grace Hopper, or you're even vaguely interested in the history of computing or women in computing, this is a must-watch:

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science
Why Are Glaciers Blue?
iStock
iStock

The bright azure blue sported by many glaciers is one of nature's most stunning hues. But how does it happen, when the snow we see is usually white? As Joe Hanson of It's Okay to Be Smart explains in the video below, the snow and ice we see mostly looks white, cloudy, or clear because all of the visible light striking its surface is reflected back to us. But glaciers have a totally different structure—their many layers of tightly compressed snow means light has to travel much further, and is scattered many times throughout the depths. As the light bounces around, the light at the red and yellow end of the spectrum gets absorbed thanks to the vibrations of the water molecules inside the ice, leaving only blue and green light behind. For the details of exactly why that happens, check out Hanson's trip to Alaska's beautiful (and endangered) Mendenhall Glacier below.

[h/t The Kid Should See This]

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