Blizzard warnings are most frequent in northwestern Iowa

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CEDAR RAPIDS, Iowa (KCRG-TV9) - A winter storm is going to bring locally heavy snow to parts of central and northern Iowa on Thursday, along with strong and gusty winds. While it’s expected to remain below blizzard levels, it won’t miss the mark by very much.

First, we have to know what makes a blizzard a blizzard. It’s when winds are sustained or frequently gusting to at least 35 mph, causing falling or blowing snow to create visibility of a quarter-mile or less. This has to happen for at least three straight hours. It turns out that snowfall amounts aren’t necessarily a factor; a blizzard can happen with a foot of snow or two inches of snow. For that matter, it can happen on a sunny day. There just needs to be enough wind and snow already on the ground to get what’s often called a “ground blizzard.”

Over the ten-year period from 2008 to 2017, the northwestern quarter of Iowa had an average of at least blizzard warning per year, while the rest of the state came in less than that. While northern Iowa does tend to have more snow over the course of the year, the wind is the big player. The higher, flatter, more wide-open terrain in that part of the state allows the wind to be stronger. So, whatever snow is on the ground is able to blow around more easily and reduce visibility.