Potentially Dangerous Winter Storm

January 26, 2013 1 Comment

If it were colder outside on Sunday afternoon, we’d be dealing with a typical late January snow storm.  Unfortunately things are going to warm up quite a bit, and that will lead to all types of precipitation during the day.  We have the potential to get more ice than snow during the day on Sunday and that will make driving extremely hazardous all day, more so than if it was just straight snow since it doesn’t really matter how good your tires are.  Everything slides on ice.

So here is the breakdown storm wise.  Early tomorrow morning in northern Iowa we will watch for freezing rain to start.  By later on in the morning that precip will move north crossing the Minnesota/Iowa border.  As it is a touch colder to the north,  things may initially start out as snow closer to the border and north before a change over to complete freezing rain.  By about the lunch hour mixed precipitation looks to be falling area wide.

While there may be a period of snow to start, it looks like much of it will fall as a mix or freezing rain.  That will cut down on any snow totals.  The better chance to see accumulating snow will be the farther north you are of highway 14.  With that said, we are still expecting ice accumulations and that is the main reason for the Warnings that are in effect.  Some will see more ice accumulations than others.  Here’s a look at how much can fall.  This will no doubt impact travel significantly, but may also cause spotty power outages across our area thanks to lines and tree limbs being weighted down and falling.

Here’s the mechanism to how freezing rain is created.  On the left side on the picture below there is a picture of a plane, helicopter, and tree.  They are there for height references.  To get freezing rain, you need precip to be occurring.  That precip will start as snow way up in the sky, getting close to where airplanes fly.  Getting closer to the Surface in a freezing rain event,  there is an intrusion of a nice wedge of warm air.  This happens just above the ground, closer to where you would see a helicopter fly.  That warm air will melt the snow flakes into rain drops.  And now the last part of freezing rain.  Below that warm wedge of air lies another cold layer of air.  that cold layer is very shallow and the rain drops don’t have time to refreeze into a snow flake or ice pellet so it hits the ground as a rain drop.  The only problem is, the ground surface is below freezing so that rain drop freezes on contact and you get ice.  You may be wondering how that warm wedge gets above the cold air in the first place.  Well I’m glad you asked.   Warm air is less dense than cold air so the warm air being brought up by a storm system will glide up over the cold air at the surface, since the warm air really can’t move the cold air out of the way.  And that’s how we get freezing rain.



In all seriousness, driving is not recommended at all tomorrow since we will likely be dealing with more ice than snow which will cause extremely dangerous travel.  Be safe and as always send us what you’re seeing on our facebook page or email us at weather@kttc.com

Keep it tuned to KTTC, KTTC.com and like our facebook page facebook.com/KTTCWeather for the latest update and potential forecast changes,  Download our new app for Android and Iphone as well to track the storm.  Search KTTC in the app store.





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  1. WIlson Lee says:

    Just went to Kwik Trip by CHS, roads are icing up but not too slick (yet!). Precip has stopped for now. Whatever leftover salt/sand from previous road treatment may hold up until the precip starts up again.

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