Comments on: Denver: Still Reeling From Last Week’s Blizzard

By: sogrady

sogrady — Fri, 29 Dec 2006 23:02:54 +0000

Bryan: reading the comment before i headed up to Keystone would indeed have saved me some time but on the modeling front, interesting; i hadn’t known the specifics beyond what was covered in the papers. and as you seem to have guessed, i was not actually trying to imply that the models were infallible or even overly accurate – merely improved. as Gleick documents in Chaos, weather is an intrinsically dynamic phenomenon, and meterologists have long been resigned to the reality that their predictions will likely always be imperfect.

By: Bryan Cantrill

Bryan Cantrill — Thu, 28 Dec 2006 07:07:31 +0000

Well, first of all you’re wishing you had read my comment before you headed for the hills expecting snow. With an upslope storm like this one, Conifer and Bailey and so on get absolutely dumped on, but that’s about as high as it goes (usually). (Historically, you could always tell the new people in town because they would head for the hills when Denver gets dumped on, not realizing that Denver got dumped on because the storm missed the hills completely.)

As for the accuracy of the computer models, I would refer you to this snippet from the most recent Denver forecast discussion:

UPDATE…LATEST 00Z NAM-WRF AND GFS RUNS HAVE NOT CHANGED A WHOLE LOT THROUGH THURSDAY NIGHT…BUT FROM THERE ON SIGNIFICANT DIFFERENCES OCCUR WITH CONSISTENCY AND LOCATION OF UPPER LEVEL FEATURES.

The GFS is the Global Forecast System model; the NAM-WRF is the North American Mesoscale Weather Research and Forecasting model, and this particular forecaster is trying to figure out the magnitude of the coming storm. If you read the discussions for Denver (especially with a big storm on the way), you’ll read about NOAA wrestling with the two (or more) models, and trying to reconcile them when they disagree (which they do, with some frequency). Which is not to say that the models haven’t improved (they obviously have) or that the computing power hasn’t increased (which it clearly has), but rather that weather is extraordinarily dynamic — and Denver’s weather especially so. So I would wager that one of the changes over the last fifteen years is a much better understanding of how to use the models, and how to make a forecast (or, more importantly, issue a watch or warning) in light of conflicting models. Finally, as for the melting of three or four feet: you’d be surprised how quickly things melt on a 60 degree day, which is not altogether uncommon in Denver in January. (The average high in January is in the high forties.) This is not to forgive the deplorable behavior of the city in this storm — only to try to give a more complete context for the handling of the storm, and to explain why this issue will likely never be satisfactorily solved. (Unless, of course, due to global climatic change or otherwise, these massive upslope storms increase in frequency — which given their origins in the warm wet air of the Gulf, I imagine is completely possible…)

By: sogrady

sogrady — Thu, 28 Dec 2006 03:29:54 +0000

Anne: i know, the side streets are unbelievably bad. i nearly got stuck – four wheel drive notwithstanding – just parking over on Eudora yesterday. it’s ridiculous.

Dave: apparently we’ve got our own history with that sort of political fallout, as Bryan points out below.

Bryan: totally appreciate both the infrequency and the climatic variables that make serious snow removal a lower priority, but that being said it was only two or three years ago that Denver got three or four feet. with that kind of snow, you can’t rely on it to melt – you need help.

now that might not, as you point out, mean permanent help, but you have to at least have contractors and private industry in place to handle the occasional spikes in demand. just like in the software business, you can’t simply throw up your hands during anomalous events – you need to find a way to add additional capacity, at a price point you can afford. and i think Denver can afford it.

interesting little tidbit from this piece, incidentally, regarding the predictability you mention: “Fifteen years ago, computer weather models occasionally predicted major storms that never materialized, but that’s rare now, Henson said.”

we’ll see if they’re right

Bill: amen. i can see impassable roads for a day or two or even three. but a week later, the roads should be clear. it’s ridiculous.

By: Bill Sullivan

Bill Sullivan — Wed, 27 Dec 2006 19:14:01 +0000

It’s the same down here in the Springs. Our whole neighborhood hasn’t been plowed at all since the storm, and I could only really drive beginning Christmas Day, although I did make an emergency trip to the supermarket the day before. I moved to Colorado about 2.5 years ago from Boston, so I certainly can’t hold a snowstorm against this state, but I can hold this mind-bogglingly inadequate response against them. Drivable roads are a fundamental part of modern life and we don’t have them in at least two Colorado cities today.

By: Bryan Cantrill

Bryan Cantrill — Wed, 27 Dec 2006 18:55:06 +0000

While I no longer live in Denver, as someone who — like you — moved there from northern New England, I feel obligated to catch you up about some Denver weather just so you don’t get too apocalyptic about the most recent blizzard. You should know that blizzards like that one only happen every three or four years or so (or even less frequently), and only when you get warm, wet Gulf air meeting cold Canadian air — the result being a big friggin’ dump on Denver and the plains. Most systems come over the Sierra, the Wasatch and the Front Range — and by the time they get to Denver, they’re out of gas. (Or moisture, as the case may be.) So the city will always — at some level — be ill-prepared for these kinds of storms, because they just don’t happen frequently enough to merit really preparing for. Yes, there will be consequences (the Blizzard of ’82 had political fallout, bringing Pena to power), but nothing will really change because the underlying meteorological phenomenona are simply too uncommon. Now, that said, it is pretty amazing that this happens to be happening twice inside of ten days (that is, if it happens). Part of the reason that there’s so much uncertainty around the forecasting of these storms is that it requires two systems — one warm and wet, one dry and cold — to collide over Denver. Growing up in Denver, there were many, many storms that were going to dump two feet but that turned into nothing. I assure you that nothing is more disappointing to a grade schooler as to go to bed thinking there’s going to be several feet and cancelled school only to wake up to two inches and school very much open. (My heart aches for the current generation of Denver kids, who must have mourned to see such an epic dump during a school vacation.)

Finally, as for why ME is much better prepared in general than Denver: in Denver, it gets above freezing in winter — a lot. So snow just doesn’t stick around (unless you have a northern exposure). Even if you get seriously nailed tomorrow night (which is not a certainty), the above-freezing temperatures will quickly melt away the consequences…

To sum, snow is not what you need to fear in Denver; what you need to fear is hail — and if you’re in Denver long enough, I trust that that will never be the subject of its own blog entry…

By: dave shields

dave shields — Wed, 27 Dec 2006 16:30:19 +0000

Remind Denver’s mayor of the New York City blizzard in February 1969. Parts of Queens went unplowed for almost a week. Many say the city’s poor response cast a permanent shadow on New York mayor John Lindsay.

By: Anne

Anne — Wed, 27 Dec 2006 16:09:18 +0000

What I don’t get is why they kept saying they plowed every side street when they didn’t even come close. No more than half of the streets in our neighborhood were plowed.

I’m picturing having this snow around through all of January… and I don’t know what I’ll do, because my minivan is rear-wheel drive with low ground clearance. Even if I could get out of our alley (unlikely, especially with more snow) I’d probably get stuck on the moguls on the streets out of our neighborhood.

It was really pretty when it first happened though. If we get another one, I suspect I won’t find it very pretty.

Have fun if you go snowshoeing.