Historic Snowstorm Becomes More Puzzling

(Image on our Super Doppler Radar around 8am February 9, 2011)

This winter has been one for the ages, especially the past 48 hours. Northwest Arkansas has topped the 24 hour snowfall record, the single storm snowfall record, and the seasonal snowfall record for at least the last 70 years. In northern Benton and Carroll County the snowstorm of March 10-12, 1968 and the 1967-68 seasonal snow totals still rival this storm and there were a couple other years in the 1910s that we believe may compare as well. Otherwise, this one takes the cake. To top it off, low temperatures just shattered all-time records a day after the storm. Whether you love or hate winter, you have to behold the once in a lifetime events for our area.

The puzzling part is trying to piece together exactly why this historic snowstorm came to fruition. As most of you know the computer models did a terrible job with the storm. Some have made note of how the NAM was the closest, which is true. On the other hand, it still missed the mesoband of snow which dropped almost all of the snowfall in northwest Arkansas. To top it all off, we all assumed that the snow was just an extremely dry or “fluffy snow” where the snow ratios were 20 to 1 or higher (meaning 1 inch of rain or liquid would equal 20″ or more of snowfall). We are now finding out that wasn’t the case. While the snow wasn’t heavy it also wasn’t as light as we thought. At my house in Springdale, I measured 20″ of snowfall, yet 3 core samples of the snow showed 1.6″ of liquid on average in the snowfall (this does not include moisture from previous snow on the ground before Tuesday). A similar measurement at our station in Rogers showed that 17″ of snowfall led to 1.55″ of liquid. This gives us a snowfall ratio between 11 to 13 to 1, which is a far cry from the expected findings. These ratios were also found at other ASOS and CoCoRaHS sites as well. While some of the observations did show higher ratios, it is still lower than expected.

So what is the big deal?

Lower ratios mean that there is a lot more moisture in the snow…moisture that wasn’t forecast by computer models. For example, about 4 to 8 times more moisture fell from the sky than what the GFS had forecasted and about 3 times more moisture fell compared to the Tuesday 00z (Monday 6pm) NAM. Literally the computer models, our lifeline for forecasting the weather beyond 24 hours, failed. This event is a unprecidented event in many ways for northwest Arkansas and now it may be the focus on future research projects as well. The reason the snow fell so hard for so long was rather simple. An extremely intense mesoband of snow lined up along highway 412 and didn’t budge for over 6 hours. What isn’t simple is understanding why the mesoband formed and more importantly why it stayed locked into place while weather all around it moved fluidly. There are things that we still don’t understand, and this is a great example of it. I am very interested to see further reasearch done on this storm, and more importantly the forecasting lessons we can take away from it. Yesterday, was one of the most humbling and surreal days of my life. One of you on here asked, if this event is a Meteorologist’s dream or nightmare…and the answer is both! While we never want to provide an inaccurate forecast, it the by far the most intense snowstorm I have ever witnessed despite living through blizzards in the Midwest and mountain snows in West Virginia. It was a delight to watch and now it will be interesting to understand the mystery behind one of Arkansas’s biggest snowstorms ever.

Ross Ellet

Follow us on twitter “4029weather”

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26 Responses

  1. I am a teacher in NWA. I took a weather class in college and your data on the blog is enjoyed! You guys do a great job and your efforts are appreciated! What impresses me is that you knew before the storm there were many variables and you admitted it! There is something to be said for that! Keep up the great work!:)

  2. Even if this storm didn’t play out the way you predicted, we still knew a storm was comming and we were prepared!! I personally think it is great all that you can predict. Look where we were 200 years ago. People were caught by surprise all the time with deadly consequences. Meteorology has alway interested me and I am continually amazed by it. Keep up the good work!!! We are always learning……

  3. I know what the deal is. The HAARP weapon in is full force. Don’t know what it is? look it up.. a new military weapon that effects the weather. Of course they won’t tell you this, but believe me it’s been proven in many documentaries… laughing are you? just wait.. weather won’t be the same from here on out.

    • You couldn’t be more wrong… what actually happened is a secret military plane carrying silver iodide crystals exploded right over Siloam Springs.

      You see if used correctly, cloud seeding can increase or decrease precip depending on what you want to happen. That is why Fort Smith always misses out on these events. The military doesn’t any storm damage to Fort Chaffee so they seed appropriately to make the storms less intense therefore decreasing the precip we get here.

      Well, a plane loaded with the silver iodide was headed to Kansas City and it disintegrated mid flight.When they all went into the developing storm at the same time, BOOM intense mesoband. And the moisture you can see on the radar “feeding” the mesoband was caused by an experimental gravity generator that was being considered for the first mission to mars.

      This all makes sense if you think about it 😉

  4. I got an email Tuesday afternoon (at 2pm) that was one of those “questionable” emails, about the expected weather. It said that the Nat. Weather Service in Tulsa knew a lot more then they were telling about the predicted snow levels. It said they didn’t want to release the info to the public because the didn’t want to panic people and have a “panicked run” on the stores. It stated that we were actually predicted to get 18-24 inches of snow. I disregarded the email until I got up on Wednesday and realized it was possibly true. Turns out it was. What do you make of that??

    • Sherrie,

      If you have the email I would like to see it, but I highly doubt the NWS new about this a day before. First of all they are looking at the same data that we are and the models did not have the potential for two feet of snowfall. Secondly, the NWS forecasted 20″ of snow for Northeast Oklahoma last week during the blizzard and nailed the forecast. When I called them at 4am on Wednesday both the NWS and myself had the same nervous tone in our voice and we were both realizing at that moment we were dealing with a monster.

      Ross Ellet

      • Nothing personal, I didn’t mean to offend and you are welcome to see the email. I just thougth it was odd. It has some names and personal info from the sender that I would rather not post here. How would you like to view it?

  5. I just want to say thank you to you guys. I know that your forecast was off, but I’m guessing when records are shattered the way they have been with this storm, that the forecast is very rarely “on” and if it is, I bet nobody believes it ahead of time anyway. It was fascinating to me, learning more about the models and how you all determine forecasts, even if they failed you this time. I look forward to hearing about any research findings for this inexplicable storm. Thank you for all your hard work, and for the updates as things began to change in the middle of the night.

    We are thoroughly enjoying the weather, and taking lots of pictures so our kids will be able to remember that they got to be a part of a record setting snow. I have seen this one other time in my life, while living in Virginia, and I’m excited that my kids get to have a similar memory. They are having a blast making snow forts and falling into drifts, which they don’t normally get to do in AR.

  6. Did you ever think that sometimes the G-O-D model may have something else in store? I am clergy, and I believe all weather is an act of God, but this one truly was. God bless.

  7. Impressive blog entry. I really appreciate the insight into the weather. We had a similar storm three years ago in north Idaho that dumped 3 feet of snow in a few hours. I’m not sure if a mesoband was responsible, but I do recall the amount of snow was not predicted and was a huge surprise.

  8. It reminds me of the winter of 1978 in southern Indiana when we had a snow that kept me stranded for three days and I lived less that an eighth of a mile from a four lane highway on a flat road! That winter and the next were the worst we ever had in Indiana to the best of my knowledge.

    • Sonny,

      I grew up in Indiana and that is all I heard about growing up was the winter’s of 1977 and 1978. Those winters still hold the records in Indiana like you mentioned. Honestly if it wasn’t for the repeated stories of the Blizzard of 1978, I am not sure I would be nearly as passionate about winter forecasting…fascinating!

      Ross Ellet

  9. Do you have video of the radar from the snowstorm? I would really like to look at looped radar footage from the snowstorm. Thank you!

    • Michelle,

      You should be able to find archived footage of the radar at this site. It will only be up for a few days though.

      http://www.rap.ucar.edu/weather/radar/

      Ross Ellet

      • Thank you!

  10. Ross,

    Previously, the models failed to handle the event appropriately for the snowstorm on Friday 2/4/10 which brought a decent swath of 5-7″ (with only an inch expected according to the NAM (who persisted with a decent band of 700 mb lift) and the GFS, which barely generated any appreciable QPF whatsoever). That being said, do you believe it is the nature of the cold airmasses (each being so cold and so dry) that the models are perhaps misinterpreting the intrusion of dry air too early? Literally, back in the day, the models converged on very similar QPF forecasts for the Ice Storm (and very early on, as well). Who is conducting research on the models’ very poor verification for this storm and what cause them to to fail the readings on the QPF? Notably, when I went to shovel the snow this afternoon from my driveway, it was not the powdery dry snow I had been expecting. Rather, it was very dense and very easy to pack. Best snowman-making snow yet for this cold season.

    • Josh,

      Friday’s storm did have a higher snow ratio and you are probably right to an extent with the models under performing due to the colder/drier atmosphere. They seemed to also struggle due to the slow moving upper-level low which had a lot to do with it.

      As for the most recent storm, perhaps it had a small impact and the upslope flow could of had a small impact as well but it still doesn’t explain why the mesoband reached extreme levels and didn’t move for 6 hours. The NWS in Tulsa will do some local research with a storm write up but I would suspect NCEP or a University may use this as a research project as well…I hope so anyways!

      Ross Ellet

      • I hope so. I’d be interested to see the results of such a project. I’m also interested in the long-term pattern change that seems to be occurring, given that the true spirit of La Nina has only recently begun to rear its head. And it has been cold cold (even thought it’s about to be warm warm). Also, I’m interested at how the cold has been centering itself across KS, OK, etc. this winter, with its outer fringes encompassing NWA and RV . . . seems like this should affect larger scale patterns (or rather, perhaps be a result thereof). Wonder if the AO will switch back negative later this month and if it does so while the PNA is negative . . . not sure what that implies for us. What I’m watching now is for the models to lock in on a couple or few weeks from now — often, with troughs hanging up in Southern California or points west, we can get a set up for a large-scale overrunning event (ex. 2009 ice storm). But being March and all, the cold air will have a harder time undercutting southwest upper flow . . . but it’s always something to watch. The potential fly in the ointment there is that La Nina’s typically don’t permit deep digging of western troughs into the East Pacific region (or if they do, it’s anomalous??). I could be wrong, but seems like there will be an ice storm near or over us at some point. In recent years, March has borne some of its own interesting winter weather phenomena. Guess I’ll keep in touch and keep an eye on your forecasts and blog. Thanks for the great forecasting and public outreach to the whole 4029 weather forecasting crew!!!

  11. I’m curious – what effect does a large area of snow cover like we have now have on surface temperatures, say compared to if there was no snow on the ground at all? Can it make it’s own weather to some degree? Thanks!

    • Neil,

      It has a huge impact. Fresh snow is a great reflector of shortwave radaiation. Melting has a cooling effect at the surface. At night with a clear sky and a light wind, temperatures can drop to extreme levels. Forecasting temperatures is very difficult with snow on the ground.

      Drew Michaels

  12. Great post Ross! I am fascinated by the way we use models to try to forecast and especially the triangulating around the different ones. This one is one I’ll call an “outlier” (yes, I am a statistician by trade), and it’s really cool to see that this storm will be used to help better understand future modeling. I also want to thank you so much for taking the time to use this blog to educate us on the science of weather in real, everyday terms!
    ps hope your parents a bundled up..we’re having cold weather here in MI as well (but again, not as cold as there!)

  13. Ross,
    Have you had a chance to look at Monday’s run of KATV’s Futurecast model? I know it’s only one run, and the next run had lower snowfall amounts. But it was pretty accurate for the NW, giving fayetteville 15″. Do you think that is merely a coincidence or was it hitting on something that other models were not? Here is the link to their blog if you want to check it out, its towards the bottom of their page.

    http://www.katv.com/Global/category.asp?C=192879

    • Daniel,

      That is interesting. It still overdid snow amounts in the river valley and underdid totals in NWA a little, but it is better than any other model that I have seen. It may of been hitting on something here. That “futurecast model” that KATV is using is a local model that has better resolution than most models and perhaps on that particular run it was trying to deal with a mesoband of some sort in NWA to the best of its ability while the GFS, Canadian, and Euro were just incapable of doing so.

      Ross Ellet

  14. I know what happened. At 1:30pm on Tuesday a UA professor, fresh from the Northeast, threw up his hands in class and said “It’s just like those rumors that we’re getting 20 inches of snow tomorrow. We’ll only get five…not that the reaction here will be any different!” (He’s apparently less than impressed by our “Well, hopefully it will melt” method of snow management.) And so the weather gods laughed, and made sure we got 20 inches of snow.

    Can’t WAIT for class next Tuesday to blame this all on him. 🙂

  15. This is really amazing information.

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