Snow!

Colorado peak questions, condition requests and other info.
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Burkart
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Re: Snow!

Post by Burkart »

DArcyS wrote: Wed Jul 14, 2021 7:48 pm Initially I was wondering about snow in relation to the monsoon. If there's a strong monsoon flow, I would "guess" the odds for snow go down, since snow in the summer probably requires a strong cold front from the north. But how does the monsoon interact with northerly fronts? I don't know, I'm not a meteorologist, I don't have access to past weather data, so I can really only "guess." :)
DArcyS, you've got the right idea here. The important thing to remember about the North American Monsoon in the US is that it is not so much a "season" as it is a highly variable weather pattern that sometimes or frequently occurs during that season; this is especially true in Colorado, which is on the northern fringe of the northern fringe of the NAM. Globally, the monsoon is the northward shift of the high pressure subtropical ridge, which can result in a complete reversal of prevailing winds in places like India. Locally, the northern fringes of a monsoon pattern will depend on where the nearest subtropical high is and how it interacts with other patterns like the jet stream. Our "typical" monsoon pattern in CO, based on the "typical" location of the high, shifts the winds from easterly to southerly or southeasterly.

This map (https://earth.nullschool.net/#2021/06/2 ... ,46.48,895) shows the wind pattern and temperature at the 500 mb level (~18,700 ft) around the time of the snow dusting that spurred this thread. The subtropical high is blocked all the way up over the Pacific Northwest (making it hot and dry there), the winds are totally reversed over eastern Oregon and NorCal, and the jet stream is wrapped around the high (bringing cold, northerly winds south to CO). This is a monsoon pattern, but definitely not our (or anybody's) typical one.

Gambling with weather is dangerous, but I'll buy a drink for anyone who can dig through the historic data on that website and find me an example of late summer snow caused by a typical CO monsoon pattern (that is, southerly or southeasterly winds). Based on the fundamentals, such a scenario should be near enough impossible to call it impossible (at least as far as a physicist is concerned :-D ).
SursumDeorsum
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Re: Snow!

Post by SursumDeorsum »

DArcyS wrote: Mon Jun 28, 2021 1:30 pm I've seen snow on peaks through the first week of July. (Shoot, I remember waking up to snow in camp over a Fourth of July weekend in 1995). And I've seen snow on peaks the first week of August (mind you, that would be real snow, not hail or graupel).

Now I'm wondering about snow on peaks in the last part of July. This represents the peak of summer, and perhaps it would be really, really hard for it to snow in the Colorado Rockies if the air currents that bring the warm monsoon moisture from the south almost always block cold air from the north that leads to actual snow. Just a thought...

Any opinions or recollection of snow the last two weeks of July?

We were hit by a brief flurry of snow just as I got to the top of Grays on July 28th 2018 — the sun came out right away afterwards and none of it stuck, but while it lasted it was pretty intense and everybody was hunkering down in the summit shelter. If there had been more if I imagine it would have been pretty annoying; but five to ten minutes of swirling snow at just that moment was actually a lot of fun, a pretty magical atmosphere in which to summit my first fourteener!
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Scott P
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Re: Snow!

Post by Scott P »

Sherman got dusted last night, but it's already gone.
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two lunches
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Re: Snow!

Post by two lunches »

DArcyS wrote: Mon Jun 28, 2021 1:30 pm Any opinions or recollection of snow the last two weeks of July?
i got snowed on at the summit of Handies on July 19, 2020. it wasn't anything measurable, but it was most certainly snow- not graupel, sleet, or freezing rain.
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Re: Snow!

Post by DArcyS »

Burkart wrote: Fri Jul 16, 2021 11:06 am DArcyS, you've got the right idea here.
Scott P wrote: Fri Jul 23, 2021 8:34 am Sherman got dusted last night, but it's already gone.
stephakett wrote: Fri Jul 23, 2021 9:47 am i got snowed on at the summit of Handies on July 19, 2020. it wasn't anything measurable, but it was most certainly snow- not graupel, sleet, or freezing rain.
Thanks all for your feedback. So, it's possible, but if we were to plot the probability of snow in the Colorado Rockies, I suspect a minimum that trends towards the height of the monsoon season, i.e., the last week of July/the first week of August. Although I'd go with the last week of July, as it seems like you can begin to detect a hint of fall very early in the mornings in August. Or maybe the third week of July just because it's warmer? Trying to pinpoint it to a week, hmm, maybe splitting hairs.

And again, Scott, thanks for reaching out to me with a pm when it appeared I was getting a little bit cranky. :-D
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Scott P
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Re: Snow!

Post by Scott P »

It snowed these on the peaks west of Buffalo Peaks this afternoon/early evening. I was on my way back from a hiking a trail on the lower slopes of the Buffalo Peaks when I took this photo of a peak to the west. It was taken 20 minutes ago (just before 5 PM).
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It's socked in again so maybe still snowing. This might be Waverly Mountain? I don't have with me that goes that far west.

The other mountains were too socked in to see which other ones got snow.

Edit: Now that I'm driving back I can see that several peaks in the Mosquitoes have a dusting of snow.
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Scott P
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Re: Snow!

Post by Scott P »

Mt Sherman right now.
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This is the third time in three days that Sherman has gotten a dusting.
I'm old, slow and fat. Unfortunately, those are my good qualities.
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