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Tag: ice formation

  • Inside Hail Formation

    Inside Hail Formation

    Conventional wisdom suggests that hailstones form over the course of repeated trips up and down through a storm, but a new study suggests that formation method is less common than assumed. Researchers studied the isotope signatures in the layers of 27 hailstones to work out each stone’s formation history. They found that most hailstones (N = 16) grew without any reversal in direction. Another 7 only saw a single period when upwinds lifted them, and only 1 of the hailstones had cycled down-and-up more than once. They did find, however, that hailstones larger than 25mm (1 inch) in diameter had at least one period of growth during lifting.

    So smaller hailstones likely don’t cycle up and down in a storm, but the largest (and most destructive) hailstones will climb at least once before their final descent. (Image credit: D. Trinks; research credit: X. Lin et al.; via Gizmodo)

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  • Winter in Chicago

    Winter in Chicago

    Fresh winter snow blankets Chicago in this satellite image. Over on Lake Michigan, ice dots the coastline out to about 20 kilometers from shore. Darker regions near land mark thinner ice being pushed outward by the wind. Further out, the ice appears white and may be thicker thanks to wind-driven ice piling up. (Image credit: M. Garrison; via NASA Earth Observatory)

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  • Growing Ice

    Growing Ice

    While much attention is given to the summer loss of sea ice, the birth of new ice in the fall is also critical. Ice loss in the summer leaves oceans warmer and waves larger since wind can blow across longer open stretches. Those warmer waters and more dynamic waves affect how ice forms once autumn sets in. Higher waves mean that ice tends to form in “pancakes” like those seen here. Pancake ice is small — typically under 1 meter wide — and can only be observed from nearby, since they’re smaller than typical satellite resolution. Only once there’s enough pancake ice to dampen the waves will the pieces begin to cement together to form larger pieces that will form the basis of the year’s new ice. (Image credit: M. Smith; see also Eos)

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  • Slipping Ice Streams

    Slipping Ice Streams

    The Northeast Greenland Ice Stream provides about 12% of the island’s annual ice discharge, and so far, models cannot accurately capture just how quickly the ice moves. Researchers deployed a fiber-optic cable into a borehole and set explosive charges on the ice to capture images of its interior through seismology. But in the process, they measured seismic events that didn’t correspond to the team’s charges.

    Instead, the researchers identified the signals as small, cascading icequakes that were undetectable from the surface. The quakes were signs of ice locally sticking and slipping — a failure mode that current models don’t capture. Moreover, the team was able to isolate each event to distinct layers of the ice, all of which corresponded to ice strata affected by volcanic ash (note the dark streak in the ice core image above). Whenever a volcanic eruption spread ash on the ice, it created a weaker layer. Even after hundreds more meters of ice have formed atop these weaker layers, the ice still breaks first in those layers, which may account for the ice stream’s higher-than-predicted flow. (Image credit: L. Warzecha/LWimages; research credit: A. Fichtner et al.; via Eos)

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  • Featured Video Play Icon

    “Lively”

    In “Lively,” filmmaker Christopher Dormoy zooms in on ice. He shows ice forming and melting, capturing bubbles and their trails, as well as the subtle flows that go on in and around the ice. By introducing blue dye, he highlights some of the internal flows we would otherwise miss. (Video and image credit: C. Dormoy)

  • Peering Inside a Hailstone

    Peering Inside a Hailstone

    In spring and summer, major thunderstorms can include dangerous and destructive hailstones. In Catalonia, a group of scientists collected hailstones after a record-breaking 2022 storm, finding some as large as 12 centimeters across. Using a dentist’s CT scanner, they looked at the interior of the hailstones, uncovering layers that reveal how the hail grew. In the past, researchers have studied hail by slicing the ice; that method gives them only a single cross-section through the hailstone, which gets destroyed in the process. In contrast, a CT scan revealed the full interior of the ice.

    The scientists found that, even though hail often appears spherical, the nucleus of the hail is not always located in the center. They saw that the hail grew in uneven layers that varied in density, depending on the storm conditions the hail experienced. To get to the enormous sizes seen here, hailstones have to travel up and down repeatedly through a storm, building up layer by layer. From the hail’s interior structure, the team could also tell what orientation the hail took its final fall in; the ice along the bottom of the hailstone was bubble-free, indicating that it collected as water drops hit the surface and froze. (Image credit: T. Ribas; research credit: C. BarquΓ© et al.; via New Scientist)

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  • Trapped in Ice

    Trapped in Ice

    On lake bottoms, decaying matter produces methane and other gases that get caught as bubbles when the water freezes. In liquid form, water is excellent at dissolving gases, but they come out of solution when the molecules freeze. In the arctic, these bubbles form wild, layered patterns like these captured by photographer Jan Erik Waider in a lake on the edge of Iceland’s SkaftafellsjΓΆkull glacier. Unlike the bubbles that form in our fridges’ icemakers, these bubbles are large enough that they take on complicated shapes. I especially love the ones that leave a visible trail of where the bubble shifted during the freezing process. (Image credit: J. Waider; via Colossal)

  • Ice Without Gravity

    Ice Without Gravity

    Astronaut Don Pettit is back in space, and that means lots of awesome microgravity experiments. Here, he grew thin wafers of ice in microgravity in a -95 degree Celsius freezer. Then he took the ice wafers and photographed them between crossed polarizers, creating this colorful image. The colors highlight different crystal orientations within the ice and give us a hint about how the freezing front formed and expanded. I can’t wait to see more examples! (Image credit: D. Pettit/NASA; via Ars Technica; submitted by J. Shoer)

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  • First Ice

    First Ice

    The early light of dawn illuminates ice forming at the edge of this pond in Vermont. Caught after a frigid mid-November night, the ice is some of winter’s first. The interface between seasons reflects the interface in water phases. (Image credit: A. Raeder; via CUPOTY)

  • Bubbles Encased in Ice

    Bubbles Encased in Ice

    If you’ve ever made ice in a freezer, you’ve probably noticed the streaks of frozen bubbles inside the ice. In its liquid state, water is good at dissolving various gases — like the carbon dioxide in sparkling water. During freezing, though, those gases cannot remain in solution; the water simply doesn’t have space between its crystalline ice lattice for non-water molecules. So the gases are forced out of solution, where they form bubbles. The final shape of the frozen bubble depends on the interplay between the speed of a bubble’s growth and how quickly the ice freezes. Here, the researchers used polarized light to outline the bubbles in color, highlighting the wide array of possible shapes. (Image credit: J. Meijer and D. Lohse; via GoSM)