The tallest point in South Korea is not located in the Taebaek Mountains<\/a> that run along the country\u2019s eastern coast<\/a>. Rather, it is found atop a volcanic peak on Jeju Island, about 100 kilometers (60 miles) south of the Korean Peninsula. In winter 2026, winds blew past the island in just the right way to send clouds spinning in its wake.<\/p>\n The\u00a0MODIS<\/a>\u00a0(Moderate Resolution Imaging Spectroradiometer) on NASA\u2019s\u00a0Terra<\/a>\u00a0satellite captured this image of swirling clouds\u2014and colorful, turbulent water\u2014near Jeju Island on February 19, 2026. The island rises about 1,950 meters (6,400 feet) above the sea surface. At its center is Hallasan<\/a>, a shield volcano that last erupted in the 11th century and contains a notable network of lava tubes<\/a>.<\/p>\n The trailing, staggered spirals, called von K\u00e1rm\u00e1n vortex streets<\/a>, form when a fluid passes a tall, isolated, stationary object. If winds are too weak, clouds simply flow smoothly past, and if winds are too strong, vortices cannot maintain their shape. In the sweet spot, with winds between\u00a018 and 54 kilometers<\/a>\u00a0(11 and 34 miles) per hour, clouds trace the airflow in patterns of counterrotating vortices. Though the underlying physics is the same, the appearance of the vortices can vary: sometimes they look wispy, as they do here, and other times they form more sharply defined, parallel rows, as they did at the same location the previous day<\/a>.<\/p>\n The seas, as well as the atmosphere, were turbulent near Jeju Island in mid-February. To the west, a large plume of sediment coming off the coast of China\u2019s Jiangsu province turned waters murky. While brown, sediment-laden water is present in the shallow nearshore area year-round, expansive plumes like this one are common during winter<\/a>. Research suggests that seasonal changes in currents<\/a> and vertical mixing<\/a> of the water column may account for the large winter plumes.<\/p>\n NASA Earth Observatory image by Michala Garrison, using MODIS data from NASA\u00a0EOSDIS LANCE<\/a>\u00a0and\u00a0GIBS\/Worldview<\/a>. Story by Lindsey Doermann.<\/em><\/p>\n![\"A](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/esd\/eo\/images\/iotd\/2026\/showy-spirals-around-jeju-island\/cloudvortices_tmo_20260219_lrg.jpg?w=2160&h=1440&fit=clip&crop=faces%2Cfocalpoint\")
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