Is There a Name for this Unusual Weather Phenomenon?

… And how often does it occur?

An article in the February 14th edition of the Springfield, Illinois State Journal-Register mentioned an interesting incident that took place in December, 1840-something.

According to an obscure tome of Sangamon County history, Joe Pioneer was riding his horse into Springfield to purchase his marriage license. The weather was ±40F and drizzling (not unusual for December in central Illinois). On the way into town, he notices a black cloud toward the west and hears a rumbling sound. A few minutes later, a cold front moves in and he is instantly frozen to his saddle as the temperature drops to ±0F. The writer of the SJ-R article postulates that the temperature dropped 40 degrees in about one second.

Sounds like bullshit to me. First of all, a black cloud in the west in the winter means that it’s about to get warmer, not colder, as it means that a warm front is bringing precipitation. It’s when high-pressure and cold fronts clear the skies of clouds that it gets really cold. Secondly, I’ve heard of drastic temperature changes (like gaining or losing as much as 70 degrees F) over the course of a day (or even an hour), but not 40 degrees in one second.

Any closet meteorologists heard of this phenomenon? How often does it happen? When & where was the last time it happened in modern times?


I believe it’s called a Chinook wind.

I’m not sure it there’s a name for it, but according to this page (at the bottom of the page), in 1943 in Spearfish, SD the temperature fell from 54 F to -4 F in 27 minutes. It was shortly after a “chinook wind” had come through, raising the temp about 49 degrees in two minutes. Perhaps the term could be “after-chinook.”

I’d be incredibly surprised if this phenomenon occurred in IL, though. Chinook winds are always associated with mountainous regions and air inversions (similar effects have been noted in Switzerland, for example.)

A sudden drop in temperature can occur due to hail storms, but not nearly that rapid, that extreme, and would usually start at a much higher temperature than 40F.

Most liekly there was a drastic drp in temp and the guy did freeze to his saddle, but most likely not instantaniously…

I live in Calgary, Alberta. We’re probably one of only a couple of places in the world that suffer/benefit from the Chinook winds (at least, as strongly as they come here).

We get some pretty whacky weather from time to time.

I’ve personally stood in Nose Hill Park (a large scrub-brush and prairie-grass foothill from where you can see a fair bit of the city) and seen four different distinct weather patterns (hail, snow, clear sky, and thunderstorm) competing for supremacy. Of course, the city’s quite spread out, so maybe this isn’t really that unusual.

However, the Chinook brings the most dramatic actual change. We’ve been in -25 degree Celsius (-13F) weather during a particularly nasty cold stretch, with hard caked snow on the ground, ice, black ice, the whole nasty ball of wax) and suddenly had it shoot up 30 degrees to 5C (41F) in only a couple of hours. It happened a couple of weeks ago when my father was here for a visit, and most of the existing snow and ice, at least on the roads, vanished.

Turn this around… there was one summer I remember, either last year or the year before, where it was something like 30C (86F), which is on the high side for any extended stretch here. It was pretty much dead center of the summer. It was, therefore, somewhat surprising when we had a classic Reverse Chinook, and the temperature dropped down around 25 degrees to a few degrees above freezing again within a couple of hours, surprising visitors to the world famous Calgary Stampede rodeo and fairgrounds with a brief snowshower. (Didn’t last, of course, and the temperature returned to normal by later that afternoon).

Changes of plus or minus 10 degrees in less than an hour are pretty routine, though thankfully not that frequent.

Let’s clear up this “Chinook wind” nonsense once and for all.

The term originated in the Pacific NW for a warm, humid, southerly wind. (The origin of the term unfortunately maligns Native Americans.) When it follows a snow storm, you can get really rapid melting.

The term has been misused recently for dry winds coming off the east side of mountains. That is clearly a completely different situation than a Chinook wind.

If you are on the east side of the Rockies, and your local weather idiot refers to Chinook winds incorrectly, let him/her know of the misuse of the term in no uncertain terms.

Well, fine, provide whatever weather term you wish to substitute in for the mountain winds that deliver the goofy temperature changes in both directions over Calgary. If its a misuse of the term, its a very very widespread misuse both by Calgary residents and the weather stations.

Are you then going to provide those of us weather-term-impaired people with a more useful term?

I found:

and there are countless others that describe Chinook in a way more or less consistent with how we use it.

If it’s an incorrect technical term, it seems to be a perfectly correct common usage term. I really don’t care what you call it – but as far as the OP is concerned, it happens, and I’ve currently got a headache because of it.

I personally experienced something like that once. My car has an outside thermometer in it. One day, I was making the 30 mile trip back home in the afternoon from South of Boston into Boston proper on I-95. It was late spring and the temperature was about 70F. All of the sudden, the thermometer started dropping about a degree every 3 or 4 seconds until it bottomed out at 40 F near Norwood, MA. I didn’t believe the reading so I rolled the window down and sure enough, it was really cold ouside. Then, just as suddenly, the thermometer started rising and it was 70 F again just a minute or so later. There were no mysterious clouds or any other obvious culprit however.

I still didn’t believe what I saw and felt, so I went home and turned on the news. The weather came on, and there was this inexplicable cold spot about 5 miles wide where I experienced it. I don’t think the meteorologist gave a proper explanation for it. It was one of the strangest thing I have ever seen.

It wouldn’t have to have dropped that fast, and it almost certainly couldn’t anyhow. If he was in relatively still air at 40 F, and a nice 30 mph wind hit him, then according to Una’s Science Tool, the wind chill would have been 28.46 F (13.2 F old method). But say that the wind was carrying in a front to him that was at 20 F, at 30 mph, and the wind chill would have been 1.3 F (-17.3 F old method) - certainly cold enough for some fast freezing.

ftg, from this site:

Are you sure about your definition? Chinooks are a very common phenomenon around these parts. I have heard natives from the Pacific Northwest refer to the dry wind as a chinook. We have a bloody mall named Chinook Centre.

I would be interested to know where you’re getting your facts. :slight_smile:

I don’t know anything about Chinook winds, but I do know that a thunderstorm is often preceded by something called a “gust front” which is a rush of cold air that flows down from the thundercloud to the ground, sometimes creating strong winds and dropping the temperature rapidly. Feels like a cold front blowing in, but it’s more localized and doesn’t last as long. But I don’t think a gust front could drop the temperature 40 degrees in one second.

You will not be frozen “instantly” at 0 deg F in any case. You will certainly be cold, but the human body has large reserves of heat not least because the specific heat of water is so high.

I will attest to this. One day in Dec., 1964, in central Illinois (Urbana-Champaign), the temperature dropped from 50 deg to 7 deg within a couple hours. A friend of mine biked in to his office in the morning wearing only a shirt and “near froze” biking home. Of course, he didn’t actually freeze and is still living happily (in Calgary, as a matter of fact) to this day. This is the most extreme temperature change I have ever experienced.

The Chinook Indians, for whom the wind, salmon, etc. are named after, lived along the lower Columbia River and adjacent areas, esp. along the OR-WA coast. (They were the richest and most powerful tribe in the PNW. They went nearly extinct by the mid-1800s, there are only a few part-Chinooks left.) This means they lived west of the Cascades and the Coast Range is too low and damp to be the origin of the term. While they traded at Celilo, just east of the gorge, they are unlikely to have been familiar with an west downslope wind at the point. (The winds in the gorge being mainly easterly.) And certainly wouldn’t have been the cause of the origin of the term. (Early explorers living north of a Chinook village on the coast caught a noseful when a south wind passed over the village middens.)

There were never any Chinook Indians in Alaska, Saskatchewan, etc. I hear “nuculer” all the time. Doesn’t make it right.

I bow to your superior knowledge of the origins of ‘Chinook’. I won’t presume to debate the point, mostly because I can’t think of a good reason to argue it further. Language mangles all things.

For the remainder of this thread, I’ll call what we experience in Calgary the Koonish winds. Inasmuch as the OP asks, the Koonish winds are very real, very weird, and quite an extreme phenomenon. Consider my previous messages retroactively mangled.

I’m afraid you won’t ‘clear up the nonsense once and for all’. The term’s being used as it’s being used (and by people who can probably pronounce nuclear). Maybe we’ll end up seeing ‘nuculer’ in the dictionary eventually… it’s dumb, but most of the English language is an amalgamation of dumb.

OK, so I’ll concede that the “obscure tome of Sangamon County history” may have exaggerated when they said Joe instantly froze to his saddle, but I see no reason for them to make up the fact that he did freeze to his saddle eventually. The article describes a 4-mile trip, which couldn’t take more than an hour on a horse. Ergo, the temperature dropped drastically enough to freeze the poor sap in less than an hour. So is there a term for a ±40F loss of temperature over the course of an hour?

Though I appreciate the mention of the Chinook/Koonish winds, those don’t happen in central IL. There are no mountains for hundreds of miles.

FTR, I once experienced about a 30-degree (F) near-instantaneous drop in temperature once, and in west-central Illinois no less. I was walking west, toward a menacing thunderstorm cloud. The temperature was ±95F. As I walked down the street, I suddenly felt a rush of cold air, almost as if I had stepped into a refrigerator (actually, the temp probably only dropped to around ±65F). I figure I stepped into the cold front that was bringing the approaching storm (which, BTW, was an awesome thunderboomer).

It’s called a cold front. Boring, yes, but no sexier term exists.

Some cool facts: Browning, MT, Jan 23-14, 1916. Themperature fell from 44 above (F) to -56 in 24 hours. 100 degrees in one day. Thats the record for the U.S.

In the Spearfish, SD, incident mentioned above, the temp went from -4 to 45 above in 2 minutes. It was up to 54 two hours later when the front backed up and sent the temps back to -4 again in 27 minutes. This same front was responsible for temperatures in Lead, SD to be 54 above while Deadwood (2 miles away) was at -16 F.

I really think what some of you are thinking of is a gust front, as I mentioned in my previous post. Look here. It is not the same as a cold front, though it may certainly feel like one.

He said ‘frozen to the saddle’, which implies that water actually froze, rather than the exaggeration “I’m freezing”.

No matter what the wind chill is, it won’t actually freeze things unless the air temperature is below zero.