The bomb cyclone that pummeled Colorado and killed a state trooper on Wednesday is now traveling east, unleashing snow, rain, and powerful winds through the midwest today. It’s a “historic March blizzard,” the National Weather Service says — and satellites have captured eerie views of the storm from space.
It’s called a “bomb cyclone” because of the rapid drop in pressure at the center of the storm, according to Jennifer Francis, a senior scientist at the Woods Hole Research Center. If a storm’s pressure drops by more than 24 millibars over 24 hours, then it qualifies. “And that definitely happened,” Francis says. Readings in Colorado on Wednesday showed pressure drops of over 30 millibars, according to Denver’s CBS4.
It’s strange to see this kind of storm over the central US, according to the National Oceanic and Atmospheric Administration. And NOAA’s GOES-16 satellite captured the unusual “bombogenesis” as the storm swirled.
The massive pressure difference between the center of the storm and surrounding areas creates strong winds, according to Francis. “Think of the center of this storm as a crater in the Earth,” Francis says. “The steeper the sides of the crater, the stronger the winds are.” Those strong winds churned up dust over Texas, which USA Today warned “will reduce visibility to less than a mile at times.” Satellite imagery captured yesterday evening shows the dust over Texas in dark pink.
The storm has been scattering lightning across the central US as well. The GOES-16 satellite picked up the flashes with the Geostationary Lightning Mapper, which is constantly keeping watch for lightning over the US.
The storm formed thanks to a massive north-south wiggle in the polar jet stream, a band of wind in the upper atmosphere that typically runs west to east across the US. That wiggle lets the polar jet stream tap into the energy of the subtropical jet stream’s heat and moisture, Francis says. “Both of those things together, when they line up just right, can touch off one of these very strong storms,” she says.
This storm, at least, is losing steam as surface pressures climb back up again. “It’s definitely in its death cycle,” Francis says. “It will move off into central and eastern Canada and weaken.”