Ice Jam Floods

When do you expect flooding?

It depends very much on where you are, of course, and what causes the flooding. Here in interior Alaska we have two flood seasons, with two quite different mechanisms, and we’re starting into one of them now, at the driest time of the year.

Yes, April is our driest month and May, while a little wetter, is the second driest month with temperatures above freezing. So why flooding now? Why not in the rainiest month, August, which did produce the great Fairbanks Flood of 1967?

Two words: ice jams.

We’re already getting some information on river breakup and flood warnings. In fact, there is an ice jam flood advisory on the Tanana River near the mouth of the Salcha (upstream of Fairbanks) today and tomorrow. Most of the rivers in Alaska run from highlands with snow — lots of snow — in the winter months to coasts that during the spring are a lot colder than the interior where the snow is melting under the sun. The snow melts and the meltwater runs into the river while the lower reaches of the river are still frozen. As the river rises and the sun weakens the ice that has covered it over the winter, the ice breaks into chunks and slabs and begins to flow with the river. It used to be axiomatic that rivers could not be crossed, and bridges were often swept away, during breakup, when the ice is carried downriver. When I came to Fairbanks it was still a possibility that the last car of the year over the ice bridge across the Chena River would go through the ice. The great gambling event of the Alaskan Spring is the Nenana Ice Pool – wagering on the exact day, hour, and minute that the ice will go out at Nenana, Alaska.

But all that ice moving downriver can cause problems, too. It’s not wimpy, thin ice; the ice at Nenana is over 2’ thick today, and while it’s thinned from is original 3 ½ feet, it still makes big chunks. If it piles up, as may happen at a different place every year, the flow of water is severely impeded, and the water spreads out over the adjacent land. Rivers in Alaska are transportation corridors – not only for boats in the summer, but for dog teams and snow machines in the winter. Consequently most of the older settlements in Alaska are on this precursor to our skimpy road net, and they almost expect to be flooded in spring. Fuel lines and tanks must be tied down, as must boardwalks, lest they float off. Belongings are put up high. I expect the public service announcements warning residents to prepare for flooding to start soon.

By the way, notice that our wettest month has an average precipitation of under 2″, and the annual total is only 10.31″. In terms of total precipitation, I live in a desert.

North Pole Weather, 4/16/12

Sunrise this morning was 6:10 pm, with sunset not until 9:33 this afternoon for 15 hours 23 minutes of daylight. We’re still gaining almost 7 minutes a day, but the snow, while pretty wet lately, is far from gone. The snow stake shows just under a foot still on the ground. There’s been enough melting that the path to the shed (and the tricycle) is impossible to shovel – it’s ice. Too bad, as they’ve plowed the bicycle path, though the tenth of a mile of dirt road to get to it is a horrible mixture of mud, ice, and potholes. But the edges of the raised beds are poking out of the snow, and at this rate I’ll be able to see the soil in the beds beds themselves pretty soon. It was actually above freezing this morning at 7 am.

I’ve started wearing my athletic shoes when I go anywhere, just tossing the boots in the car in case I encounter ice. I’m actually getting to attend evening functions, like The Stoned Guest (P.D.Q. Bach) Friday night. I need to start the beans next week, and the squash the week after that. Time to start visiting the greenhouses, too – I rely on them for culinary herb plants and flowers.

If only I weren’t so busy with OLLI classes this month! Northern vegetation changes and archaeological science Monday, iPhoto and digital photography Wednesday, astrophysics Friday, and a weekend workshop on fiction writing at the beginning of next month. Hope I can remember to keep the plants watered!

p.s. at 4 pm: temperature +57°F and I had to take off my jacket and turn on the air conditioning driving home! Still plenty of snow, though — the snow stake says 8″, though lots of bare ground, as well as mud and puddles,  are showing.

Breakup Season

The usual four seasons, especially as defined by the equinoxes and solstices, don’t work very well for interior Alaska. Show cover is generally established by a month after the autumnal equinox, and stays on the ground until well after the vernal equinox. Rivers freeze a little later and remain frozen longer in the spring, and the only running water for six months of the year is in hot springs and indoors. But there is one season that everyone both longs for and dreads: Breakup.

Breakup is the time of year when snow melts and rivers thaw. The two are connected by more than sunshine and warmer weather. Melting snow makes mud (one of the reasons breakup is a time of some dread) but it also runs into rivers. If the water rises in the upper stretches of a river before lower reaches are thawed, as often happens in Alaska, the result can be ice jams and resultant flooding. I’ll talk about that some other time, but right now I want to discuss the simple process of melting snow.

Clean snow reflects most of the solar energy that strikes it. Some of the sun’s rays are absorbed within the snow pack, and cause internal melting and settling — but this is a slow process. Even clean snow, however, is a very good absorber in thermal infrared wavelengths. The sun doesn’t put out much energy in these wavelengths, but buildings, trees, and just about everything else except polished metal does. As a result, snow near the south side of a building melts much faster than snow out in the open. So does snow near tree trunks.

I see this every year. In addition to the photo of my road, which is rapidly turning into mud, I took two of the north and south yards of my house, minutes apart. Both areas got almost exactly the same amount of snow, and both have very similar exposure to sunlight. The snow stake still has a good 18” of snow. The ground around the birch is almost bare.

Why? Two reasons, actually, and the combination explains why open birch forest is usually the first natural area free of snow around here. First, birch trees hold their seeds through winter, and drop them shortly before breakup. As a result the seeds on the snow around the tree absorb the solar radiation and transfer that energy to the snow, speeding its melt. Natural selection? Quite possibly. It certainly seems likely that the enhanced snow melt, leading to earlier warming of the ground, would help the tree.

Second, the tree itself absorbs some solar energy, and then re-radiates it to the snow in the form of thermal infrared. Just about any object poking through the snow this time of year has a little depression around it. Spruce trees do an even better job of absorbing sunlight than do birches, but they also shade the ground and transfer much of the energy they absorb directly to the air. As a result spruce forest, while it probably does a better job of warming the air than birch forest, is among the last areas to have completely bare ground.

On a different note entirely, one of the fixtures of breakup in Fairbanks is the Beat Beethoven 5 km race, a fundraiser held today for and by the Fairbanks Symphony Orchestra. I won’t be running this year, though I did “run” with a cane once — and came in last. The idea is to cover the 5 km before the end of Beethoven’s 5th Symphony, about 30 minutes. I’m volunteering this year to park my car along the race route with the radio tuned to 91.5 (KSUA, the campus radio station) blaring out Beethoven’s 5th. I expect temperatures below 50°F and much of the course to be slippery or wet!

Added later (after the race.) This is definitely a family race. There were parents pushing their children in strollers, parents with children in backpacks or riding piggyback, dogs, and one contestant on crutches. (And she wasn’t at the end, either.) I did have a bit of a problem in that instruction to volunteers said if possible, not to have your car idling as the runner went by. I did. And needed a jump to start the car after the battery totally discharged itself.

Cold-packed Snow: White Ice

This pile of white ice chunks was scraped off the OLLI parking lot. As you can see, the lot is still white.

I’ve talked about snow that is undisturbed without a temperature gradient, and about disturbed snow without pressure. Today we’re going to take that a step farther and look at snow that is disturbed by pressure—specifically, by car or foot traffic—when temperatures are below freezing. Here in Alaska we call it white ice, and the less-traveled roads and almost all the parking lots are solid white ice this time of year.

Wind or an avalanche will break snow crystals, but it doesn’t in itself press the broken grains together. Walking or driving over dry snow, however, not only breaks the crystals, it also presses them together. If it is near freezing, the pressure may even cause slight melting. In any event the crystals are very firmly welded together. The result is a mass that has some air trapped—that’s why it looks white. But it may be only a little less dense than ice, and is only slightly softer. An icebreaker or a sharp-edged shovel will generally break it much more easily than it will break true ice, but white ice is definitely solid.

Some of the chunks of white ice removed from the road I live on.

As a driving surface, white ice is something most Alaskan drivers learn to deal with. It is not impossibly slippery if it is not polished or near freezing temperature, though most of us drive on it with caution and learn to feather our brakes. Mine are anti-skid, but I’ve learned to brake softly enough that the anti-lock feature almost never engages—except at intersections.  Those are often polished to the point that they are extremely slick, even though graveled.

Yes, graveled. We don’t use salt much because our temperatures are generally so low that even salt water freezes and salt simply will not melt ice. Salt’s used on sidewalks sometimes, but in cold weather each salt pellet simply melts its way down to the pavement without having much effect on the main ice mass—except to make it slicker.

Notice the step left when one lane of my road was plowed a couple of days ago.

The road I live on is gravel, and a coating of white ice actually improves it. But it does do some things you might not think about to paved roads.

First, it covers any marking painted on the road or parking lot—lane markings, turn arrows, lines that mark parking spaces.

Second, it can at times be thick enough that when part of a road is cleared in the spring, a considerable drop-off may result.

Third, and especially a problem when it is overcast and the light is flat, is whiteout conditions. It’s not as bad as in an airplane north of tree line when the pilot may not even be able to see which way is up, but telling what is road and what is not can be very difficult when the road is white ice and the verge is snow and both are exactly the same color. It’s hard to see even with directional light and shadows, but in flat light everything looks the same.

I managed to high-center my car a few weeks ago taking an exit between a four-lane highway and a major side road. The exit was pure white ice, and I couldn’t quite see what was road and what was the curbed triangle between the side road and the exit. I wound up on the triangle and had to be pulled off by a tow truck. Neither the trooper who stopped to see if I needed help nor the tow truck driver seemed to have the slightest problem understanding how I’d gotten there, or even consider my situation unusual. “Whiteout”  was all the explanation I needed.

Disturbance Hardening of Snow

Ever notice that the berm across the end of your driveway, or the one formed when you shovel the sidewalk, is harder than the undisturbed snow? That’s because when snow is disturbed crystals are broken, and the broken surfaces positively grab onto other ice surfaces. Two examples of this are common in nature, and I’ve used both in my fiction writing.

The first is called a wind slab or wind crust. When a turbulent wind picks up snow crystals and redeposits them, a good deal of crystal breakage takes place. When the broken crystals settle down they weld themselves to other crystals and the result can be a hard crust—even though the temperature is below freezing. Roi has to cope with this in Tourist Trap:

The trees had broken the force of the wind up to now, but once he entered the open swath the wind almost knocked him off his feet. The snow was crusted here, not quite enough to hold his weight, but enough that his thighs were bruised repeatedly by the chunks of wind-slabbed snow he was dragging Timi through. He paused twice to increase the circulation to his feet. Were they cold, hurting like hell, or just numb? he wondered absently, and then realized that Timi’s shields had dropped to the point that he was feeling Timi’s body as well as his own. The wind cut through the frozen scarf and the cold glued his eyelashes shut, and with a start of horror he realized that he had drifted away from the line back to the shelter. He could teleport himself back, maybe—but he wasn’t sure he had the energy left to do even that, and there was no way he could take Timi with him.

He struggled on: lift a leg and break the crust with his knee, then drag the leg through the slightly softer snow underneath until he could balance on that leg to break out the next step with the other leg. Timi staggered behind him, almost falling several times, and his mind ached from the effort of keeping the other boy upright. Snow had sifted into his clothing, somehow, and he knew he was cold but no longer felt it. With an abruptness that caught him by surprise, the wind died down, and he went to his knees as he tried to break through a crust that was no longer there. Back in the trees, he finally realized, and reached out for the faint impression of the shelter.

The second is probably less familiar to most, and I hope it remains so, but here in Alaska it is constantly being drummed into us. This is what happens in an avalanche. The churning snow sets up like concrete as soon as it comes to a halt. Well, not quite like concrete — it can be dug through with shovels – but far too hard to shift by moving your body. Marna is caught in an avalanche in Homecoming:

Even as she crouched and aimed herself for a belt of trees that might provide some protection, the leading edge of the avalanche overran her, tumbling her helplessly down the slope. The churning snow caught and twisted one forceweb until she thought her leg would break, but the torsion activated the safety cutoffs and the forcewebs went abruptly inert. She clawed her way upward through the fast-moving snow, and tried to remember what lay downhill. Only her perceptive sense kept her from total disorientation.

The buffeting and spinning as she was carried along reminded her of the time she had been caught in the breaking wave—but then Win had been there to rescue her. Win. She had repudiated whatever was left of Win, but as the slowing mass suddenly set rigidly about her body, she wondered at her own insanity in wanting to be alone. She struggled to move, but felt only the slight snapping of a switch, followed by the growing cold of the snow that held her prisoner. Her struggles must have turned off the thermal suit, she realized with a growing sense of despair. Exhausted and chilled, she could not even visualize a place of safety. Win, she sobbed mentally. Forgive me, my love.

This is a situation where time is absolutely essential, and buried but living victims are likely to die of suffocation or cold – often in less time than it takes to get help. Dogs are better than people at finding victims, but if search and rescue dogs have to be flown in, it is often too late to find anything but a body.

World Ice Art Chapionships Multi-block 2

Here are the sixth through the tenth placings in the 2012 World Ice Art Championships, along with a few shots of the general layout of the competition site.

Sixth place went to “Geoflames,” sculpted by a USA team.

Seventh place was “Playin’ in the Garden,” again by a team from the USA. This one had a “viewing window” (actually three atop each other) to indicate the best place to see the sculpture. This photo was taken through that window, also carved from ice.

Eighth place went to “The Super Raven Guide.” The two carvers were from Russia, and it took me a while to see the raven’s head. I was trying to make it an aurora, and it may have been intended to evoke one. Most of the sculptures were done by teams of four. This and the fourth place “The Land Calls” a couple of days ago were carved by 2-person teams.

Ninth place and Artist Choice was “Spring.” I’ve used this one before, but it’s worth using again. The artists on this one were from China.

Tenth Place and Governor’s Award was “Olde #7 On The Bridge To Nowhere.” The artists were from the USA.

The ice as cut from the pond has a layer of cloudy ice  near the surface, where snow and ice intermingle. Although most sculptors cut this off, it can be used with interesting effect, as on this pedestal.

Finally a wider view of part of the competition area. Snow is being blown off  “Mother” in this picture. I’ll have at least one more blog on the kids’ area of the ice park by daylight, and I might get to see it at night, lit up, next week. If I do, I’ll get some pictures. The sculptures are incredible bathed in colored lights in the dark. If you’d like to see a particular piece under the colored lights, leave a comment. No promises, but I’ll try.

Multi-Block Ice Sculpture 1

My internet access is via a phone line (DSL) so I am well aware that pages with lots of photos tend to load slowly. This is one reason I’ve broken the World Ice Art Championships into several blogs. (The other is that the awards for Tourist Trap are keeping me pretty busy marketing, and several short blogs are easier than one long one.) Beside, who wants to look at that many photos at once?

First place in the multi-block competition was “Prickly Reception,” by a team from Japan. Don’t ask me how they managed the porcupine. I did find out how they achieved the leopard’s frosty spots: shave out the ice, saving the shavings. Then pack the shavings back into the hollows and heat.

Second place was entitled “Rebirth of Elements.” Three of the carvers were from Russia; the fourth was from Monaco.

Third place went to “Tiger Marriage Desire.” One of the carvers was from the USA, and the other three were from China.

Fourth Place was “The Land Calls.” Both sculptors were from Russia.

Fifth Place (and one of my favorites) was “The Gallery.” One of the carvers was from the Phillipines; the other 3 were from the USA.

One question I’ve had was answered yesterday. We’ve had over a foot of snow since the carving started — why don’t the sculptures all have snow caps? The answer? Leaf blowers!

Ice Sculpture: Single Block by Daylight 2

Single block 2? Well, I couldn’t get them all in one post, so I split them up. Some of these were taken from the train (which bounced badly, so I hope they aren’t too blurred.) I’m going to use larger photos this time, in hopes they won’t change places!

This was 7^th place, “Giving Thanks to the Great Spirit.”

8^th place was “Dragontango.”

9^th place was “Spirits of our Ancestors. The shoulder and beard at the far left belong to the train driver.

10^th place was “Pegasus in Sky.” This one was definitely taken from the train.

“Entertainment” took the Artists’ Choice award.

“Your Move” is a hero-and-dragon theme, always popular.

“Unrest” really showcases the ice.

“Feather” is another that caught my eye. Notice that all of the single-block sculptures are set among trees, for protection from the sun.

No, that’s not all of the photos I took. Next week I’ll show the progress of the multi-block sculptures, which are sculpted from up to 10 blocks of ice, each 6’ x 4’ by 3’. The judging was yesterday evening, when the sculptures were lighted. Will I have any photos of the lighted sculptures? Depends on whether I can hitch a ride after dark.

Ice Art Championships 1

The Ice Art Championships are underway! I’ll show some of the competition pieces next Saturday. But I did pick up a season pass and have a look at the kids’ park. If the weather cooperates, I hope to get some photos of more than just this bit close to the entrance.

This one's very interactive--kids (including some quite large ones) can get into the dish and be spun around.

For a while we were afraid we’d lose the World Ice Art Championships. They’ve been held for years on land owned by the Alaska Railroad. Something happened last year—I think the railroad raised the rent, but I’m not sure, and for a while the organizers were frantically hunting a new site. Well, they’ve found a permanent home and while it’s still rather raw, it promises to be as spectacular as the old one.

This one is actually a slide. Sorry there isn't more contrast with the sky.

As I said, I only got to see the kids’ park Saturday, but I did take a few photos. Even the slides and the sculptures to climb on are pretty neat. The train sounds like a good idea once I figure out where the station is. I went again on Monday, and got some more photos of the kids’ park, plus took enough more for several more posts. Watch for them.

Isn’t our Alaskan ice beautifully clear?

Note: you can click on any of the photos to see larger versions.

The sabertooth cat can be ridden, but you'd better have insulated pants!

This dragon is saddled and ready for kids to ride.

More slides

Guess who sponsored this one!

North Pole Weather 3/5/12

Ice bird carving in front of the hospital lab.

The sun rose at 7:43 this morning and will set at 6:22 for 10 hours 39 minutes of daylight. Spring may not be here officially, but sun on snow was almost too bright to look at Sunday. My snow stake agrees with the official snow depth: 20”. That’s actually not too bad for this time of year; not so much that it will take forever to melt, but enough to insulate the ground from getting any colder. Regretfully, I’ll be back to “sun will rise” next week—this post goes live at 8 am my time, and daylight savings will once again put sunrise before I get up. Only for the one week, though. We’re gaining 6 min 45 sec a day, and by March 19 I’ll again be getting up after sunrise.

It’s been on the cold side—temperatures above zero in the middle of the day but well below zero at night. No sign of melting yet, and I’m going to try to photograph the ice sculptures before they start thawing this year. (Watch for tomorrow’s post.) They are, however, beginning to accumulate snow. Never very much at a time, but we seem to get a fraction of an inch a day rather often this year.

The commonest real birds this time of year.

I ordered my bean and squash seeds yesterday. Rocdor (yellow) and Gina (Italian type), both of which I know do well up here, and are actually earlier than the regular green beans, are my bean varieties of choice; Gold Rush and Contender for zucchini. I enjoy visiting the local greenhouses too much to order seeds for herbs and flowers I know will be available as starts locally. Besides, I try to avoid pesticides indoors, and my seedlings almost always get bugs if I try to grow too many.

WriteMotivation:

My goals for March were:

1. Learn to use at least one legal method of getting images other than photos I’ve taken on my blog. (I’d love to have some shots of Africa on Jarn’s Journal, for instance.) Progress? Mostly looking up creative commons on Google, and finding a few pictures I’d like to use. I’ve also talked to a friend about using some of his African photos.

2. Continue to blog at least 5 days a week. (I’m doing 7 now, but I’ve signed up for a number of adult classes in March.) Progress? So far I’ve blogged every day and have posts lined up for 10 of the remaining 26 days.

3. Edit Chs 2 and 9 of my WIP to give more showing, less telling. Progress? I think I have Ch 2 done.

4. Participate in at least one Platform-building challenge–hesitate to commit for more without knowing what they are. Progress? I accepted the first Campaign Challenge and posted the result. Not sure if achieving this goal in February counts, though.

And I received notice that my second novel, Tourist Trap, is a finalist in the Reader Views Literary Awards contest! So I’m on track, at least.