Anatomy of a Mega-Blizzard: Top 5 snowfall in Madison; Cold through Christmas week

1 foot plus snowfall totals common from Des Moines through Madison & Tomah, Wisconsin

18.5" snowfall at Middleton near Madison - highest storm total

13.3" snowfall 2nd highest 1-day snowfall ever record at Madison

15.2" snowfall 4th highest 2-day snowfall total on record at Madison

16.6" snowfall 8th highest 3-day storm total on record at Madison

13.8" snowfall at Des Moines NWS office

2.54" liquid in Milwaukee highest three day total ever recorded for December in Milwaukee

46.9% of the lower 48 USA Area Covered By Snow:

5.4% of the lower 48 USA Area Covered Last Month:

White Christmas assured for most of the northern half of the USA

Real winter is here cold & quiet through Christmas Day

Decent winter travel conditions through Christmas Eve in the Upper Midwest

Christmas Eve light snow chance?

2nd chance of snow next Friday December 28th

(Click all images to enlage for a better view)

Anatomy of a Mega-Blizzard:

You could see this one coming a long way off, and it was one for the record books.

The widespread, long lasting blizzard left a trail of deep snowfall in its wake from Colorado through Nebraska, Iowa, southeast Minnesota & Wisconsin.

The 36 hours radar loop from the La Crosse NWS show the evolution of the storm as it plows through the Upper Midwest.

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Image: La Crosse NWS

Metro Close Shave:

You can see how the Twin Cities rode the northern fringe of this powerful storm, and why systems like this can give us meteorologists premature grey hair. A shift of just 50-70 miles in the storm track either way is literally the difference between no snow, and nearly a foot.

Image: La Crosse NWS

Rapid "Cyclogenesis":

The system was deepening as it moved northeast into the Upper Midwest. The system nearly achieved "bomb cyclogenesis" status as it deepened rapidly.

The Milwaukee NWS elaborates:

Image: Milwaukee NWS

The small 2 digit numbers next the "L" is the pressure in millibars with the "9" missing. So, "82" would be 982 mb, which was the lowest pressure in the storm when it was crossing the Chicago area. The storm deepened 1 millibar per hour for 15 hours. Storms that strengthen 1 mb per hour or more for at least 24 hours are considered "explosive cyclogenesis", a technical term for rapidly deepening storms that are relatively rare. So, although this storm did not meet the criteria, it came rather close. The times are in UTC or Zulu, so 18z along the CO/KS border is Noon Wed, 00z over Kansas was 6 pm Wed, etc.

Impressive system:

This system had all the ingredients to produce heavy snow and blizzard conditions. The low sucked in deep moisture from the Gulf, and cold air from behind.

Heavy snow set up about 60 to 120 miles north of the low track.

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Image: La Crosse NWS

Prolific snowfall totals:

What do you get when you mix a potent low, deep moisture with enough cold air to "spin up" the system? A foot of snow.

The heaviest snowfall totals ran in a band from near Des Moines into Wisconsin.

Image: Des Moines NWS

Image: La Crosse NWS

Image: Milwaukee NWS

Madison: Ground Zero

The heaviest snowfall totals came down near Madison, Wisconsin. 18.5" ...a foot and a half fell at Middleton in Dane County.

Madison set several snowfall "top 10" records with this storm.

More details from the Milwaukee NWS.

Madison recorded 13.3 inches of snow on Thursday, December 20th, which broke the previous record of 4.6 inches, set in 2000.

That one day total was the 2nd highest one day snowfall total in Madison! The record is 17.3 inches, set on December 3rd, 1990.

The two day total of 15.2 inches from Wednesday, December 19th to Thursday, December 20th was the 4th highest two day total in Madison! The record is 17.3 inches, set on December 2nd and 3rd, 1990.

The three day total of 16.6 inches from Tuesday, December 18th to Thursday, December 20th was the 8th highest three day total in Madison! The record is 19.0 inches, set on February 23rd, 24th and 25th, 1994.

Drought Buster:

How do you bust a drought? One big sloppy storm at a time.

The prolific snowfall totals contain 1" to 2" of liquid water. That will melt and help dwindling Mississippi River levels in the months to come. On the warmer side of the system, record December rainfall drenched Milwaukee & southern Wisconsin, sending rivers to bankfull, and drenching some still unfrozen soils.

Image: Milwaukee NWS

The three day total of 2.54 inches from Tuesday, December 18th to Thursday, December 20th was the highest three day total for December in Milwaukee! The old record was 2.46 inches, set on December 2nd, 3rd and 4th, 1982.

Rain amounts of 1.50 to over 2.00 inches, southeast of a line from Ozaukee County to Walworth County, caused water levels in most rivers and streams to rise to near bankfull or bankfull. However, flood stages were not reached, due to the snow and colder temperatures halting runoff. The liquid equivalent totals across the rest of the area were high as well, with amounts of 0.75 inches to around 2.00 inches. This illustrated the high water content in the snow that fell, which resulted in the "heavy and wet" snow.

White Christmas tracker: In the bag all the way south to Kansas City?

The storm dumped snow as far south as Kansas City, St. Louis and central Illinois.

Image: NASA MODIS Terra via UW Madison

Some melting will occur on the southern fringes by Christmas Day, but this storm assured a white Christmas for much of Colorado, Nebraska, Iowa, and Wisconsin.

Image: NOHRSC

Winter in Minnesota, from space:

Friday's NASA MODIS Terra image shows Minnesota's wintery landscape from space.

Image: UW Madison

You can see frozen Mille Lacs, and a black Lake Minnetonka. That is either still open water, and some really nicely forming black ice, but still unsafe in many spots.

Open water on Tonka on the Winter Solstice:

I checked the big "main" portion of the "Lower Lake" on Minnetonka today, and my ground truth confirms the MODIS view of open water on Tonka.

"Main" Lower Lake Minnetonka on the winter solstice 2012. Boken ice, new smoother ice, and open water from Sandy Beach in Cottagewood.

Image: Paul Huttner - MPR News

This is pretty late for the big lake to freeze up...but not unprecedented.

I asked Dick Gray, the founder of the Freshwater Society in Navarre and a long time ice watcher about freeze up. Dick explains that lakes freeze up much more erratically than "ice out" in spring.

Hi Paul - Gleason Lake is a relatively small lake that joins Lake Minnetonka under Wayzata, Mn. I live on Gleason and have for 18 years, after living on the western shores of Lake Minnetonka for 40-odd years. One thing I've learned about ice-in dates is it's impossible to fix any certain date for any certain year.

It's a rare year to have a lake of any size freeze over on any date, let alone stay frozen for the rest of the winter. When the ice goes out, you know it. When the lake freezes you know it only after watching part or all of the lake freeze and refreeze totally 2 or more times. I have records of ice-in for Lake Mtka and surrounding lakes, ponds and puddles and finally gave up on recording any one date for any one year.

There was one year many years ago that Mtka froze over safely everyplace and one could skate from one end the to other and into any bay with at least 5-6 inches of ice on Christmas Day There are other years iceboating and fish houses with occupants in cars were not safe with open water all over the place, especially at or in passages between one or more of the 15 "main" lakes that comprise Lake Minnetonka. This condition went into January but a final freeze-over date was impossible to document.

I assure you I would have kept track of ice-in dates if they made sense but they usually don't. For instance.on Sunday, November 25, 2012, Gleason froze up to 95%, Mtka none. Since then, Gleason has opened up and then nearly froze 2 or 3 times and was 100% frozen this morning, December 18, 2012.

Minnetonka still has lots of open water, especially that of the Lower Lake. It has a ways to go. In the open reach between Wayzata and Excelsior in the Lower Lake. a good wind will wipe out "young ice". It takes several days of freezing weather and little or no wind to have the whole lake freeze. I would suggest ice-in dates that include several days - for instance Dec.10-27, although the lake is usually frozen by Christmas but many times is not.

Mtka is so heavily used by all kinds of activity it's dangerous to cater to ice-in for all uses, such as cars on the lake, snowmobiles rounding points and entering passages. Huge schools of fish - mostly carp- keep the water churning and eats away at the ice from beneath the ice. You've got 112 miles of shoreline and almost as many variables to keep the lake open. Sorry not to be of a better help to you. Merry Christmas !!!

Dick Gray

That was actually very helpful Dick!

Thanks to you, and for all that you have done from the days I used to read your Passwords column in the Lake Minnetonka Sailor as a teenager.

You've done so much to educate Minnesotans about water in our Land of 10,000 Lakes... and even helped to inspire one young lad from Deephaven who went on to become a local meteorologist for WCCO-TV and MPR.

Thank you, and Merry Christmas Dick!

Skaters enjoy smooth ice on Carsons Bay on Lake Minnetonka on the winter solstice.

Image: Paul Huttner - MPR News

Making ice through Christmas:

The arrival of true winter air masses will stay with us through Christmas week. Highs will stay in the teens and low 20s, and overnight lows in the single digits above zero will help build lake ice in the next week.

The recent cold has brought some of the best lake ice in years to the inner bays of Lake Minnetonka, and other metro lakes. Skaters and ice boaters will have plenty of fresh, clean, smooth, "snow free" early season ice this year. Just be sure you know the ice is safe enough for what you're doing.

Not sure? Ask an ice fisherman nearby who has drilled some holes.

I'm away next week for the holiday. My partner in weather crime Craig Edwards will be your guide as we work through Christmas week.

A very Merry Christmas and Happy Holidays to you and yours!

PH