Black Hills Winter Storm Forecast: Discussion, Impacts, Timeline

Spring is kicking in the front door with Heavy snow, gusty winds and possible record low temperatures just in time for Easter

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  • Before we dig in, lets establish that everyone will see different timelines, with areas North of the Black Hills already seeing a mix of rain and snow.
  • For Black Hills, Rapid City and Northeastern Wyoming, most action should hold off until the afternoon and evening hours.
  • Showers are already moving through, with temperatures expected to drop as we move through the morning and afternoon from the 40s, to the 30s and eventually 20s and teens overnight into Sunday.

Here’s a quick look at current radar and road conditions.

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  • Winter Storm Warnings and Advisories have been posted for the Hills and surrounding areas, with Carter County, MT, Harding, Perkins, and Ziebach Counties the most recent additions Saturday morning.
  • Most impacts are expected to center around the Black hills and areas South of the Hills, with areas of the Bighorns in Wyoming expecting widespread impacts as well.
  • These warnings and advisories are expected to continue through Noon Sunday, with the exception begin areas North of the Black Hills which could see advisories expire as soon as 6 AM Sunday.

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  • Diving right in, The first part of Saturday will be relatively busy North of I-90, with rain and snow bands already passing through the region this morning.
  • Areas South of I-90, including the Hills, could theoretically see relatively dry conditions all the way through the afternoon.

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  • Temperatures will begin to drop this afternoon from North to South. These temperatures will not recover, and as we push into Saturday evening a bitterly cold wind will drive wind chills down, quickly.

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  • By late this afternoon a mixture of snow, sleet gusty winds and deteriorating road conditions will move into the Black Hills.
  • Things start filling in for northeastern Wyoming as well, with areas South of the Hills still seeing mostly rain at this point. This will change quickly.

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  • A chilly Easterly/Northeasterly wind will pick up this afternoon, with gusts up to 30 MPH.
  • This will sock in moisture, and make things feel wet and cold, particularly East of the Black Hills and in the Northern and Eastern Foothills.

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  • By 7-9 PM this evening, we’re in it. Heavy snow bands, with low visibility and snow rates of 1″-2″ per HOUR will be possible during this time period in and around the Black Hills

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  • Temperatures have plummeted to the 20s across the area by 10 pm tonight, with teens starting to creep in the higher elevations.
  • Snow consistency will change from a heavy wet snow to a powdery, blowing and drifting mess as winds start to pick up.
  • Once winds start clocking out of the North this evening, things will quickly start to get very cold, with wind Chills starting to approach the single digits across the plains.

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  • Early Sunday morning will see familiar dynamics grip the region, with stubborn upslope snow pushing into the Northern and Eastern foothills and an equal area of down slope dry pockets in the Southwestern portions of the Black Hills.

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  • With Blowing and drifting snow, bitterly cold wind chills and icy/snowy roads… even people with essential travel destinations may not be able to move from their spot at this point.
  • Temperatures have dropped into the teens and lower twenties, will powdery and light snow blowing across interstates and highways.

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  • Winds will continue to clock Northerly into Sunday morning – with upslope snow continuing so long as those winds stay Northerly.
  • Once winds turn Northwesterly, sometime Sunday morning, dry air will start to undercut snow potential and bring relief.

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  • Not all snow will be gone though, areas of blustery snow showers will still be hunting for unsuspecting travelers Sunday afternoon/evening.
  • By this time though, accumulating snow has pretty much ended and we’re looking at cold, dry and windy conditions Sunday evening.

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SNOW ACCUMULATIONS

  • The I-90 corridor between Sundance and Rapid City will once again be socked in to high snow potential thanks to geographical features of the Black Hills and associated Northeasterly/Northerly Winds.
  • Look for anywhere from 6″ of snow to upwards of 10″… possibly even more as you step just South and west of I-90. This includes areas of Johnson Siding, Nemo, Whitewood, and Tilford.
  • Areas of the Central and Northern Hills, including Lead, Deadwood, Silver City, Rochford, Cheyenne Crossing and Spearfish Canyon could easily hit a foot of snow, with obvious variations depending on what side of the street you’re standing on. Just know that travel will be difficult… even if you only get 11″ of snow.
  • Rapid City could see 6″-10″ of snow, with Western areas of town seeing higher accumulations… but areas East of town seeing higher drifts.
  • Box Elder… this will be another situation where most of your snow is gathered on the Northern side of your house, and your lawn on the South side is relatively clear. Strap down anything that moves.

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  • On that subject, winds whipping around the Northern and Eastern flank of the Black Hills could see Northwesterly and Northerly gusts as high as 45 MPH, with significant blowing and drifting snow possible. (we are shy of blizzard conditions here, but caution is strongly advised regardless as there could be periods of very unsettling conditions that resemble as such.)
  • This, in my opinion, will be one of the most difficult areas of travel Saturday night going into Sunday morning. These whipping winds could circle all the way around, stratching down SD-79 towards Hermosa, Fairburn and Buffalo Gap.

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  • A noticeable dry pocket will develop in portions of the Western and Southwestern Hills, with Newcastle, Edgemont, and Western areas of Custer County seeing a sharp cutoff.
  • This cutoff could dig as far North as Deerfield, but anything North of that will be a completely different story.
  • Having that said, just discretion if you must travel.. this storm can sneak up on anyone in this region!

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  • A strategic view of our battle lines shows most of the higher accumulations in the Black Hills, the foothills and areas south of I-90.
  • I could see areas of Harding, Perkins and Ziebach County getting some isolated pockets of 4″-6″.. but I think this will be more the exception than the rule.
  • Northeastern Wyoming will see higher accumulations the closer you are to the Bighorns, with Gillette in a “relative” dry pocket of only 2″-4″ accumulations expected. (still expecting gusty winds though… don’t let your guard down)
  • Oglala Lakota, Jackson and Bennett Counties will see strong variations of 4″-7″.. with some pockets of 6″-9″ being very possible, especially towards the Martin community.
  • Fall River county is tricky, that dry pocket will extend Eastward and stop at some point… my guess is right before or just on the outskirts of Hot Springs… I’m throwing 3″-6″ of snow for you all… with higher accumulations as you move South towards Oelrichs.
  • Hill City, Custer and Custer State Park could see more than 4″-7″ of snow… but with that sharp cutoff, I think we’ll see higher amounts of 6″-9″ or even more once you hit Custer, heading North towards Hill City. Pringle could see that dry pocket take those accumulation down to 3″-6″

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FORECAST DISCUSSION

Full disclosure, this storm gives me pause. Accumulation numbers have gone up, and haven’t stopped since Wednesday evening. There’s nothing to say that we couldn’t see forecasted conditions ramp up just a bit more before things finally move in. If you’re working outside in these conditions as calving season gets underway… be prepared from some pretty gnarly conditions. Treat this winter storm with the respect you would for a once a season storm, as I think this will be the one people remember when they think of Spring 2020.

Dry pockets will prevent some areas from seeing anything significant….. possibly deep into the afternoon. Don’t let this fool you… it’s coming and any plans for travel this evening should be put on hold – particularly in the Black Hills and areas South of I-90. One of the biggest things we want to keep in mind are the gusty winds and bitterly cold temperatures that will move in tonight going into Sunday. Even if you don’t get a large amount of snow, these will be difficult conditions to work in. Winds will clock Northeast, North, and then eventually Northwest towards Sunday morning in the South Dakota plains.

Big shout out to truckers, ranchers, first responders and those keeping civilization running through pandemics, snowstorms and whatever else mother nature throws at us. This forecast is for you all. Everyone else is going to do our part; stay home, and in turn keeping as many folks out of harms way as possible. Let the plows do their work, if you absolutely must travel, check in on road conditions and radar before you do so.

Send in your pictures! The National Weather Service can use this data to provide critical information to highway patrol, first responders, and those trying to keep the roads open. Let us know your location, and how much snow you’ve received so far.

As per usual, we appreciate you checking in with us for… what is for some a critically important forecast. We understand that when we put this information together, it leads to important financial and manpower choices for those working in these conditions. We take that charge seriously.

Be safe out there folks. – Brant

 

 

 

 

 

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