Meet Asperitas, the Newest Addition to the Cloud Atlas

Kirill Ignatyev via Flickr Creative Commons // CC BY-NC 2.0
Kirill Ignatyev via Flickr Creative Commons // CC BY-NC 2.0

Cloud-spotters, rejoice! After years of lobbying, the World Meteorological Organization (WMO) has granted Asperitas formations a spot in the official cloud canon. The change is part of an update to the International Cloud Atlas released for World Meteorological Day on March 23.

The first iteration of the cloud atlas, published in the late 19th century, laid down the scientific standards for the monitoring and measurements of clouds and other meteorological phenomena. It formalized the system of taxonomy introduced by an amateur cloud-spotter in 1802, which mirrored the classification of plants and animals by sorting clouds into 10 major types, or genera, then splitting them further into varieties and species.

The last edition of the atlas was published in 1987. The clouds may not have changed since then, but the world has, and the WMO wants to keep up. The new edition will be all-online and include measurements and data from 191 different countries and territories. It will also feature one new species—the volutus, or tube-shaped cloud—and five supplementary features, including asperitas.

The inclusion of asperitas is a point of pride for Cloud Appreciation Society founder Gavin Pretor-Pinney, who says members have been sending in photos of asperitas-covered skies for more than a decade.

“Ever since we first noticed distinctive turbulent waves of cloud back in 2006 in images sent from Cedar Rapids, Iowa, US, we have argued that this formation did not easily fit within the existing naming system,” CAS noted on its website. “So we are very pleased that now, almost ten years later, asperitas is finally being accepted as an official classification by the World Meteorological Organisation.”

The taxonomy of clouds may sound fluffy to laypeople, but experts like WMO secretary-general Petteri Talaas take it very seriously. “If we want to forecast weather, we have to understand clouds,” he said in a statement. “If we want to model the climate system, we have to understand clouds. And if we want to predict the ability of water resources, we have to understand clouds.”

The theme of this year’s World Meteorological Day was—you guessed it—Understanding Clouds.

Spotted something spectacular? Check out the CAS website or the WMO’s submission guidelines to share it with the cloud-loving world.

Storm Leaves Homes Along Lake Erie Covered in Up To Three Feet of Ice

Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
John Normile/Getty Images

This past weekend, lakeside residents of Hamburg, New York, awoke to find their neighborhood transformed into a full-scale replica of Frozen’s ice-covered kingdom, Arendelle.

According to CNN, gale force winds produced giant waves that sprayed the houses along Lake Erie with sheets of water for two days straight, covering them in layers of ice up to three feet thick.

“It looks fake, it looks surreal,” Hamburg resident Ed Mis told CNN. “It’s dark on the inside of my house. It can be a little eerie, a little frightening.”

While the homeowners are anxious for the ice to melt, they’re also concerned about what could happen when it does.

“We’re worried about the integrity, of structure failure when it starts to melt, because of the weight on the roof,” Mis said.

He added that this is the worst ice coating he’s seen since he moved to the area eight years ago—but it’s not because they’ve had a particularly harsh winter. In fact, just the opposite is true. According to The Detroit News, warm winter temperatures have caused ice cover on the Great Lakes to drop from 67 percent in 2019 to less than 20 percent this year.

“Lake Erie typically has significant ice cover by this time of the year, and that protects the shoreline from these battering storms,” The Weather Channel’s winter weather expert Tom Niziol explained in a video.

The phenomenon has created another unforeseen issue for Hamburg’s coast, too: Tourism. The local police department posted a message on Facebook on Sunday, March 1, asking people to keep off both the “extremely unsafe and unstable” ice and people's private property.

[h/t CNN]

What is Lake-Effect Snow?

Tainar/iStock via Getty Images
Tainar/iStock via Getty Images

As you probably guessed, you need a lake to experience lake-effect snow. The primary factor in creating lake-effect snow is a temperature difference between the lake and the air above it. Because water has a high specific heat, it warms and cools much more slowly than the air around it. All summer, the sun heats the lake, which stays warm deep into autumn. When air temperatures dip, we get the necessary temperature difference for lake-effect snow.

As the cool air passes over the lake, moisture from the water evaporates and the air directly above the surface heats up. This warm, wet air rises and condenses, quickly forming heavy clouds. The rate of change in temperature as you move up through the air is known as the "lapse rate"; the greater the lapse rate, the more unstable a system is—and the more prone it is to create weather events.

Encountering the shore only exacerbates the situation. Increased friction causes the wind to slow down and clouds to "pile up" while hills and variable topography push air up even more dramatically, causing more cooling and more condensation.

The other major factors that determine the particulars of a lake-effect snowstorm are the orientation of the wind and the specific lake. Winds blowing along the length of a lake create greater "fetch," the area of water over which the wind blows, and thus more extreme storms like the one currently pummeling the Buffalo area. The constraints of the lake itself create stark boundaries between heavy snow and just a few flurries and literal walls of snow that advance onto the shore. The southern and eastern shores of the Great Lakes are considered "snow belts" because, with winds prevailing from the northwest, these areas tend to get hit the hardest.

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