Iowa is currently within the grip of a brutal stretch of cold weather spanning the New Year’s holiday. Let’s take a look at how this cold snap stacks up against others from the past, with a focus on Des Moines where the climate record is longest. As of 10 pm on 01/01/2018, here are the observed high and low temperatures for Des Moines (through the the 1st) plus forecast values through tomorrow (the 2nd):

Day Low High 12/30 -5 5 12/31 -15 -2 01/01 -19 -1 01/02 -17* 15*

(*forecast value)

Already several daily records have been set at Des Moines. On 12/31 the low temperature record was tied at -15 (previously 1968) and the “cold high” record was broken with a high of only -2 (previously -1 in 1968). On 01/01 the low temperature record was also broken at -19 (previously -18 in 1887). In other words, this is as cold as it gets for New Year’s in Des Moines.

So, when is the last time we saw cold of this magnitude on any date? The answer is, it depends on how you measure it. In the 19th and early 20th century truly extreme cold events were somewhat more common and measured in areas much more prone to cold temps, ie - Forts in river valleys. (Since 1939 - Des Moines official measurement has been taken at the Airport.) The last of these was the epic cold wave of 1912, in which Iowa set its all-time record low temperature when Washta fell to -47 degrees on 01/12. That’s temperature, not wind chill. Since 1912, the most extreme cold snap experienced in Iowa came in 1996. Many long-time Iowa residents will remember that legendary event when pipes froze, cars died, and roads cracked apart in the cold. On 02/03/1996 the Osborne Conservation Center southwest of Elkader, Iowa hit -47 degrees, tying the all-time state record that was set in 1912. Here are the daily high and low temperatures for Des Moines during the 1996 cold wave:

Date Low High 01/30 -13 1 01/31 -21 0 02/01 -12 -1 02/02 -24 -9 02/03 -26 -9 02/04 -20 15

Only twice in the climate record has Des Moines experienced three consecutive days of -20 degrees or lower, the other being in January of 1883. Since the 1912 cold outbreak the two coldest readings at Des Moines have been the -26 and -24 listed above (it also reached -24 on 01/21/1970).

Clearly, the 1996 event was exceptional, and dwarfed even the current brutal cold stretch (as can be seen by comparing the two tables above). However, since 1996 the current event is certainly one of the coldest, if not the coldest snap we have experienced. In terms of the coldest 24-hour period, New Year’s 2017-2018 has essentially tied January 15-16, 2009 when the high on the 15th was -4 and the low on the 16th was -19. In terms of a multi-day cold event, we are certainly in the midst of the coldest stretch since 1996. Here is how the two-day, threeday, and four-day average temperatures at Des Moines (including *forecast* values for today and tomorrow) stacks up against other events since 1996:

Coldest 2-day: -9.3 on 12/31-01/01 (previously -5.7 in 2009) Coldest 3-day: -6.5 on 12/31-01/02 (previously -3.7 in 1997) Coldest 4-day: -4.9 on 12/30-01/02 (previously -2.6 in 2010)

In other words, by most measures this is easily the most extreme cold wave experienced in Des Moines since the legendary 1996 event. Remember, the extreme cold will persist into Tuesday, so please continue to take appropriate precautions when traveling or venturing outside.

Jeff, yup cold is right!!! My kids in Ely can attest to that! But, what about a warm-up? Now that Christmas is over, I would just a soon have - - spring! Will the cold pass and than have a warming trend/ wishful thinking!!

I think it's all because you went and bought a hot tent, WhiteWolf :) Cold here in Iowa City, also, but sunny and not much wind, so not so bad, but plenty of water pipe issues, etc., going on.

I spent Christmas and the week after in Fargo ND, and it was BITE-ASS cold. I was thinking it would be nice to get back to Iowa where it would be a bit less cold. WRONG! Last night at 10:00 p.m. it was -17 in Ames and -9 in Fargo.

BTW, this cold is really hard on small dogs. We have a Chihuahua mix, and I have to put him inside my jacket, go outside, put the dog on the ground to do his business, put him back inside my jacket and go back into the house.

Heard a comment on TV the other night when they said the average daily temperature in Wausau the week between Christmas Eve and New years Day if you average the high temp with the low temp for each day and then averaged those daily temps came to -6. Today was the first day it was above 0 at 8:00 am. I'm looking forward to visiting the ice caves of Lake Superior if this continues. But first I'm going to try and start my truck.

thebotanyguy: "I spent Christmas and the week after in Fargo ND, and it was BITE-ASS cold. I was thinking it would be nice to get back to Iowa where it would be a bit less cold. WRONG! Last night at 10:00 p.m. it was -17 in Ames and -9 in Fargo.


BTW, this cold is really hard on small dogs. We have a Chihuahua mix, and I have to put him inside my jacket, go outside, put the dog on the ground to do his business, put him back inside my jacket and go back into the house.
"

Somehow I think your students would get a kick out of that, if there were a video...

Grandma L: "Jeff, yup cold is right!!! My kids in Ely can attest to that! But, what about a warm-up? Now that Christmas is over, I would just a soon have - - spring! Will the cold pass and than have a warming trend/ wishful thinking!!"

As with most "old fashioned" winters that have severe cold in late Dec or early Jan there usually is a JAN thaw. That appears to be the case this year also. The last half of JAN should see this "thaw" for most reading this. This appears very likely as of this writing. What usually happens after the "thaw" in classic winters is a reloading of the cold in Arctic and Canada and it spills south for many in early / mid FEB. Long ways to go.

A bit of embarrassing news I must admit now having been in Central IA for nearly 20 years after growing up in Minnesota. Des Moines was on pace to have it's latest occurrence of first measurable snow which is 12/26 only to have .1" reported on 12/21/17-. -Too suddenly having people complaining about the winter being "so long"?? 12 days in a row of below normal temps and 11 in a row of at least 1" of snow on the ground and people are complaining? Sad. ( for DSM last above normal day was the 22nd of Dec and 1" or more of snow on the ground has been reported since the the 24th of Dec-- fwiw the record is 94 consecutive days of 1" or more of snow on the ground for DSM ----) from Dec 7th 2009 through March 10th 2010.

Btw- Charleston,SC has seen more snow in one day this winter then Minneapolis has seen in one day this winter and very near more then Minneapolis has seen ALL winter.

Well, I would appreciate a little warmth during the super bowl stuff. We have friends coming from England and this deep freeze would be a bummer. She lived in MN for 5 years so she knows all about winter, but warmth would be welcome.

-27 air temp here in Okoboji was really fun on the 1st...made 15 degrees today feel amazing! whitewolf...I always enjoy your posts on weather thank you for sharing your knowledge on this subject.

M

I think it would be interesting to know just how much of a temperature spread there can be between two points relatively close, but geographically different. You mention temperatures used to be taken near water sources; that coupled with older methods of weather data collection could really have an impact on "real" all time lows and highs.

Do you happen to know where and what the weather measuring equipment looks like at an airport? Mounted typically by terminals or more runway specific?

Funny story related to airport weather equipment...in a 121 commercial operation, you must have a means of obtaining the official weather at your intended destination before landing. It can be clear and a million miles vis, but without the officially reported weather, your not landing there. We were off to a smaller regional airport that could be seen from 40 miles out, but ASOS was telling us reported visibility was 1/4 miles, which is below landing mins for that airport. We entered a holding pattern nearby, got ahold of our dispatch, who then got ahold of the airport personnel, who then went and cleaned the cobwebs blocking the sensor from whatever device measures the visibility. We finally got the green light and headed on in with a bit less fuel than we expected.

Soon after the 20th I'm making a swing around Chicago from the UP of Michigan and taking 80 west. I hope this thaw WW your talking about happens. I'll go straight west visiting grandkids. Then south I go. I hope to meet up with andym around Sacramento, and keep heading down to I-10 and hanging out in the Arizona-New Mexico area. I'm hoping to get this neck business under control. This -30 many mornings has been brutal on the old neck. I need relief bad! So the possible repreve is very inviting to me if it might happen to get me through to my trip.

Diego: "I think it would be interesting to know just how much of a temperature spread there can be between two points relatively close, but geographically different. You mention temperatures used to be taken near water sources; that coupled with older methods of weather data collection could really have an impact on "real" all time lows and highs.


Do you happen to know where and what the weather measuring equipment looks like at an airport? Mounted typically by terminals or more runway specific?


Funny story related to airport weather equipment...in a 121 commercial operation, you must have a means of obtaining the official weather at your intended destination before landing. It can be clear and a million miles vis, but without the officially reported weather, your not landing there. We were off to a smaller regional airport that could be seen from 40 miles out, but ASOS was telling us reported visibility was 1/4 miles, which is below landing mins for that airport. We entered a holding pattern nearby, got ahold of our dispatch, who then got ahold of the airport personnel, who then went and cleaned the cobwebs blocking the sensor from whatever device measures the visibility. We finally got the green light and headed on in with a bit less fuel than we expected.


"

They (FAA) try and put ASOS as close to the runways as possible (with guidance from the NWS as to not get too close) to have more relevant winds speed and direction for the aviation community. ASOS/AWOS is (was?) a function of the NWS but has been ruined and run down by the FAA gaining more control recently, because all they care about is saving $$ and are not into preserving climate data. Sorry for getting off topic :O) The entire 10 meter height of where the official wind speed is measured is based on the aviation community- especially the estimated crucial height of when a commercial jet is lading/taking off. In the mid 90's when ASOS was first introduced in most cases it was properly placed a ways away from climate altering situations (runways/taxiways etc.) Now with the expansion of many airports many ASOS's are being overwhelmed with expansions of concrete and if moved are not moved in a suitable location do to the FAA not caring about climate data. Long story. Attached is a pic of an ASOS capture date: 1999-08-18
Description
AT CHARLOTTE DOUGLAS AIRPORT ON WEST SIDE OF RUNWAY 136 (note the rotating anemometer) -- now replaced with IFW (ice free wind sensor) on most ASOS - though they don't freeze up they are not as reliable as birds and others like to perch on them and distort the wind speed to missing or unrepresentative.



And A current view of KDSM's ASOS from the ATC facility.

DIEGO-

your story of the cobwebs is one of hundreds I have heard from pilots over the years. The FAA could care less about wasted fuel. Only when human lives are lost do they listen.