Shallow Thoughts : tags : snow

Akkana's Musings on Open Source Computing and Technology, Science, and Nature.

Sun, 13 Jan 2019

Snowy Views and Giant Curling Icicles

[Snowy back yard] And the snow continues to fall. We got a break of a few days, but today it's snowed fairly steadily all day, adding another -- I don't know, maybe four inches? Snow is hard to measure because it piles up so unevenly, two inches here, eight there.

[Snowshoe trail, Jemez East Fork] The hiking group I'm in went snowshoeing up in the Jemez last week -- lovely! The shrubs that managed to stick up above the snow all wore coats of ice, which fell by afternoon, littering the snow around them with an extra coat of glitter.

[icicle] And it was lovely here too, with a thick blanket of snow over everything. (I need to get some snowshoes of my own, to make it easier to explore the yard when conditions get like this, otherwise the snow would be thigh-deep in places. For the hike last week, I borrowed a pair.)

[Curling icicles] And, of course, there's the never-ending fascination of watching icicles, snow glaciers moving down the roof, and, this time, huge curving icicles growing downward above the den deck. They hung more than four feet below the roof before they finally separated and fell with a huge THUMP!, leaving a three-foot-high pile of snow that poor Dave had to shovel (I helped with shoveling at first, until I slipped and sprained my wrist; it's improving, but not enough that I can shovel ice yet).
Images of the snowstorm and the showshoe hike: Snowstorms in January 2019.

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Fri, 28 Dec 2018

A Post-Christmas Snow

[Snow world] The morning after Christmas we woke up to a beautiful white world, with snow still coming down.

Shoveling is a drag, but still, the snowy landscape is so beautiful, and still such a wonderful novelty for ex-Californians.

This morning we awoke to much the same view, except the snow was deeper -- 8-12 inches, quite a lot for White Rock.

[Roof glacier hanging] We also had the usual amusement of Roof Glaciers: as the mat of snow gradually slides off the metal roof, it hangs off the edge, gradually curling, until finally the weight is great enough that it breaks off and falls. Definitely an amusing sight from inside, and fun from outside too (a few years ago I made time-lapse movies of the roof glaciers).

[Sunny New Mexican snow world] And then, this being New Mexico, the sun came out, so even while snowflakes continued to swirl down we got a bright sunny sparkly snow vista.

Yesterday, the snow stopped falling by afternoon, so Raspberry Pi Club had its usual Thursday meeting. But the second storm came in hours earlier than predicted, and driving home from Pi Club was a bit icy. I wasn't looking forward to the drive up to PEEC and back tonight in a heavier snowstorm for our planetarium talk; but PEEC has closed the Nature Center today on account of snow, which means that tonight's planetarium talk is also canceled. We'll reschedule, probably next quarter.

Happy Holidays, everyone, whether you're huddling inside watching the snow, enjoying sunny weather, or anything in between. Stay warm, and walk in beauty.

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Wed, 13 Jan 2016

Snow hiking

[Akk on snowshoes crossing the Jemez East Fork]

It's been snowing quite a bit! Radical, and fun, for a California ex-pat. But it doesn't slow down the weekly hiking group I'm in. When the weather turns white, the group switches to cross-country skiing and snowshoeing.

A few weeks ago, I tried cross-country skiing for the first time. (I've downhill skied a handful of times, so I know how, more or less, but never got very good at it. Ski areas are way too far away and way too expensive in Californian.) It was fun, but I have a chronic rotator cuff problem, probably left over from an old motorcycle injury, and found my shoulder didn't deal well with skiing. Well, the skiing was probably fine. It was probably more the falling and trying to get back up again that it didn't like.

So for the past two weeks I've tried snowshoes instead. That went just fine. It doesn't take much learning: it's just like hiking, except a little bit harder work remembering not to step on your own big feet. "Bozo goes hiking!" Dave called it, but it isn't nearly as Bozo-esque as I thought it would be.

Last week we snowshoed from a campground out to the edge of Frijoles Canyon, in a snowstorm most of the way, and ice fog -- sounds harsh when described like that, but it was lovely, and we were plenty warm when we were moving. This week, we followed the prettiest trail in the area, the East Fork of the Jemez River. In summer, it's a vibrantly green meadow with the sparkling creek snaking through it. In winter, it turns into a green and sparkling white forest. Someone took a photo of me snowshoeing across one of the many log bridges spanning the East Fork. You can't see any hint of the river itself -- it's buried in snow.

But if you hike in far enough, there's a warm spring: we're on the edge of the Valles Caldera, an old supervolcano that still has plenty of low-level geothermal activity left. The river is warm enough here that it's still running even in midwinter ... and there was a dipper there. American dippers are little birds that dive into creeks and fly under the water in search of food. They're in constant motion, diving, re-emerging, bathing, shaking off, and this dipper went about its business fifteen feet from where we were standing watching it. Someone had told me that he saw two dippers at this spot yesterday, but we were happy to get such a good look at even one.

We had lunch in a sunny spot downstream from the dipper, then headed back to the trailhead. A lovely way to spend a winter day.

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Thu, 31 Dec 2015

Weather musing, and poor insulation

It's lovely and sunny today. I was just out on the patio working on some outdoor projects; I was wearing a sweatshirt, but no jacket or hat, and the temperature seemed perfect.

Then I came inside to write about our snowstorm of a few days ago, and looked up the weather. NOAA reports it's 23°F at Los Alamos airport, last reading half an hour ago. Our notoriously inaccurate (like every one we've tried) outdoor digital thermometer says it's 26°.

Weather is crazily different here. In California, we were shivering and miserable when the temperature dropped below 60°F. We've speculated a lot on why it's so different here. The biggest difference is probably that it's usually sunny here. In the bay area, if the temperature is below 60°F it's probably because it's overcast. Direct sun makes a huge difference, especially the sun up here at 6500-7500' elevation. (It feels plenty cold at 26°F in the shade.) The thin, dry air is probably another factor, or two other factors: it's not clear what's more important, thin, dry, or both.

We did a lot of weather research when we were choosing a place to move. We thought we'd have trouble with snowy winters, and would probably want to take vacations in winter to travel to warmer climes. Turns out we didn't know anything. When we were house-hunting, we went for a hike on a 17° day, and with our normal jackets and gloves we were fine. 26° is lovely here if you're in the sun, and the rare 90° summer day, so oppressive in the Bay Area, is still fairly pleasant if you can find some shade.

But back to that storm: a few days ago, we had a snowstorm combined with killer blustery winds. The wind direction was whipping around, coming from unexpected directions -- we never get north winds here -- and it taught us some things about the new house that we hadn't realized in the nearly two years we've lived here.

[Snow coming under the bedroom door] For example, the bedroom was cold. I mean really cold. The windows on the north wall were making all kinds of funny rattling noises -- turned out some of them had leaks around their frames. There's a door on the north wall, too, that leads out onto a deck, and the area around that was pretty cold too, though I thought a lot of that was leakage through the air conditioner (which had had a cover over it, but the cover had already blown away in the winds). We put some towels around the base of the door and windows.

Thank goodness for lots of blankets and down comforters -- I was warm enough overnight, except for cold hands while reading in bed. In the morning, we pulled the towel away from the door, and discovered a small snowdrift inside the bedroom.

We knew the way that door was hung was fairly hopeless -- we've been trying to arrange for a replacement, but in New Mexico everything happens mañana -- but snowdrifts inside the room are a little extreme.

We've added some extra weatherstripping for now, and with any luck we'll get a better-hung door before the next rare north-wind snowstorm. Meanwhile, I'm enjoying today's sunshine while watching the snow melt in the yard.

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Sat, 14 Feb 2015

The Sangre de Cristos wish you a Happy Valentine's Day

[Snow hearts on the Sangre de Cristo mountains]

The snow is melting fast in the lovely sunny weather we've been having; but there's still enough snow on the Sangre de Cristos to see the dual snow hearts on the slopes of Thompson Peak above Santa Fe, wishing everyone for miles around a happy Valentine's Day.

Dave and I are celebrating for a different reason: yesterday was our 1-year anniversary of moving to New Mexico. No regrets yet! Even after a tough dirty work session clearing dead sage from the yard.

So Happy Valentine's Day, everyone! Even if you don't put much stock in commercial Hallmark holidays. As I heard someone say yesterday, "Valentine's day is coming up, and you know what that means. That's right: absolutely nothing!"

But never mind what you may think about the holiday -- you just go ahead and have a happy day anyway, y'hear? Look at whatever pretty scenery you have near you; and be sure to enjoy some good chocolate.

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Tue, 03 Feb 2015

Studying Glaciers on our Roof

[Roof glacier as it slides off the roof] A few days ago, I wrote about the snowpack we get on the roof during snowstorms:

It doesn't just sit there until it gets warm enough to melt and run off as water. Instead, the whole mass of snow moves together, gradually, down the metal roof, like a glacier.

When it gets to the edge, it still doesn't fall; it somehow stays intact, curling over and inward, until the mass is too great and it loses cohesion and a clump falls with a Clunk!

The day after I posted that, I had a chance to see what happens as the snow sheet slides off a roof if it doesn't have a long distance to fall. It folds gracefully and gradually, like a sheet.

[Underside of a roof glacier] [Underside of a roof glacier] The underside as they slide off the roof is pretty interesting, too, with varied shapes and patterns in addition to the imprinted pattern of the roof.

But does it really move like a glacier? I decided to set up a camera and film it on the move. I set the Rebel on a tripod with an AC power adaptor, pointed it out the window at a section of roof with a good snow load, plugged in the intervalometer I bought last summer, located the manual to re-learn how to program it, and set it for a 30-second interval. I ran that way for a bit over an hour -- long enough that one section of ice had detached and fallen and a new section was starting to slide down. Then I moved to another window and shot a series of the same section of snow from underneath, with a 40-second interval.

I uploaded the photos to my workstation and verified that they'd captured what I wanted. But when I stitched them into a movie, the way I'd used for my time-lapse clouds last summer, it went way too fast -- the movie was over in just a few seconds and you couldn't see what it was doing. Evidently a 30-second interval is far too slow for the motion of a roof glacier on a day in the mid-thirties.

But surely that's solvable in software? There must be a way to get avconv to make duplicates of each frame, if I don't mind that the movie come out slightly jump. I read through the avconv manual, but it wasn't very clear about this. After a lot of fiddling and googling and help from a more expert friend, I ended up with this:

avconv -r 3 -start_number 8252 -i 'img_%04d.jpg' -vcodec libx264 -r 30 timelapse.mp4

In avconv, -r specifies a frame rate for the next file, input or output, that will be specified. So -r 3 specifies the frame rate for the set of input images, -i 'img_%04d.jpg'; and then the later -r 30 overrides that 3 and sets a new frame rate for the output file, -timelapse.mp4. The start number is because the first file in my sequence is named img_8252.jpg. 30, I'm told, is a reasonable frame rate for movies intended to be watched on typical 60FPS monitors; 3 is a number I adjusted until the glacier in the movie moved at what seemed like a good speed.

The movies came out quite interesting! The main movie, from the top, is the most interesting; the one from the underside is shorter.
Roof Glacier
Roof Glacier from underneath.

I wish I had a time-lapse of that folded sheet I showed above ... but that happened overnight on the night after I made the movies. By the next morning there wasn't enough left to be worth setting up another time-lapse. But maybe one of these years I'll have a chance to catch a sheet-folding roof glacier.

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Sat, 31 Jan 2015

Snow day!

We're having a series of snow days here. On Friday, they closed the lab and all the schools; the ski hill people are rejoicing at getting some real snow at last.

[Snow-fog coming up from the Rio Grande] It's so beautiful out there. Dave and I had been worried about this business of living in snow, being wimpy Californians. But how cool (literally!) is it to wake up, look out your window and see a wintry landscape with snow-fog curling up from the Rio Grande in White Rock Canyon?

The first time we saw it, we wondered how fog can exist when the temperature is below freezing. (Though just barely below -- as I write this the nearest LANL weather station is reporting 30.9°F. But we've seen this in temperatures as low as 12°F.) I tweeted the question, and Mike Alexander found a reference that explains that freezing fog consists of supercooled droplets -- they haven't encountered a surface to freeze upon yet. Another phenomenon, ice fog, consists of floating ice crystals and only occurs below 14°F.

['Glacier' moving down the roof] It's also fun to watch the snow off the roof.

It doesn't just sit there until it gets warm enough to melt and run off as water. Instead, the whole mass of snow moves together, gradually, down the metal roof, like a glacier.

When it gets to the edge, it still doesn't fall; it somehow stays intact, curling over and inward, until the mass is too great and it loses cohesion and a clump falls with a Clunk!

[Mysterious tracks in the snow] When we do go outside, the snow has wonderful collections of tracks to try to identify. This might be a coyote who trotted past our house on the way over to the neighbors.

We see lots of rabbit tracks and a fair amount of raccoon, coyote and deer, but some are hard to identify: a tiny carnivore-type pad that might be a weasel; some straight lines that might be some kind of bird; a tail-dragging swish that could be anything. It's all new to us, and it'll be great fun learning about all these tracks as we live here longer.

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