Yesterday, a big snowstorm dumped about 30 cm (12″) of snow on Minneapolis, and high winds blew that snow around. On my way home from lab, the train worked well, but I definitely chose correctly when I decided to walk home from the train (2-3 km) rather than take the bus. The roads were a mess, but walking wasn’t too bad.
When that much snow falls that quickly, skiing can be much better for getting around than driving. After dinner I hopped on the skis to go tour around the neighborhood and enjoy being on snow for the first time this winter. I’d barely skied half a block when a car got stuck turning and I helped get them through the intersection.
Skiing around the lake was wonderful. There’s something magical about the quiet of lots of new-fallen snow, and even though the skiing was slow-going, it was fun. However, with it being dark and my being on skis for the first time this winter, I didn’t bring a camera with me.
This morning I went out again and took the camera, because there was a lot of neat stuff to be seen. After helping two more cars get unstuck, I made it to the lake. There were tracks: skis (see photo above), boots, snowshoes, and dogs, plus tire tracks in the roads. High winds had also led to drifting, so there were eolian features as well: mini-dunes, scoops, and even some parabolic or blowout features.
Scoops form when wind has to travel around an object such as a tree, rock, or the legs of a park bench. Because the wind velocity increases on the leading edge of the feature, snow or sand get removed from in front of the obstruction.
The lake is a great place to look for eolian features, because its flat surface without plants or other obstructions provides a large windy area. Miniature dunes formed, with steep faces to windward, and shallower slopes on the leeward side. In the photo of the lake above, the wind was traveling left-to-right. It also features a pair of cross-country ski tracks!
One of the neat features was this blowout on the south (leeward) side of the lake. Last night it seemed to be a fairly parabolic feature, but today it was clearly a blowout. The grasses slowed the wind and provided a place for snow to accumulate, while the gap between grass tussocks was a high-wind area. Scouring is evident near the gap, but deposition follows not far downwind, and the parabolic shape of the features is visible.
There were a few birds out and about this morning, too! A white-breasted nuthatch was foraging in a tree above me, and several other nuthatches were fluttering around nearby.
It was a fun expedition out skiing, and I was happy to take some pictures along the way. The snowplows were busy while I was out, and several of the streets had been cleared before I got back home, so there were fewer cars to help out of the deep snow.
Recently I’ve been reading an interesting book by Paul Bogard, The End of Night. It’s non-fiction, and is based around the increasing amounts of night-time light in the developed world—and why that may not be a great thing.
Just 200 years ago, before electric lights, the night sky—complete with the swath of the Milky Way, and other naked-eye observable galaxies—was spectacular on any clear night from anywhere on Earth. Today, however, few in the developed world see that a few times a year, let alone on every clear night. Instead, our nights look like they do in the photo of Berkeley above, with a milky haze of yellow-orange light from the 589 nm sodium D lines (admittedly there is some fog in the picture too).
There were four key messages I took from the book.
First, straightforwardly, is that a dark night sky is incredibly beautiful, and we should preserve that beauty. Seeing the Milky Way clearly with the naked eye can be a powerful experience especially for those who have rarely or never have. Unfortunately, very few places in western Europe (or the eastern half of the US, or populated areas in the western US) are near dark skies. Bogard cites a statistic that 80% of children born in the US today will never see a truly dark sky. In my experience as a teaching assistant at Berkeley going on a geology field trip to Bishop, CA and the eastern Sierras, I can attest to a large proportion of the students being quite surprised by all the stars visible from such dark skies.
Adding light doesn’t make it easier to see. Sure it makes it easier to see initially when you first go from the light into the dark, but if the light isn’t in the right places, it actually makes it harder to see. I have biked at night on roads where the streetlights made it very difficult for me to see the road, because the lights were so bright and everything else so dark. Glare from bad lighting makes the lighting less effective. It’s also light going places it isn’t needed or wanted, which is wasted energy (and money, and CO2 where electricity comes from fossil fuels). The picture at top has a number of lights shining directly into the camera, miles away; all that light is wasted and unneeded. Bedrooms have light streaming in from outside even at night, which causes its own problems.
People are evolutionarily adapted to sleep at night, and our bodies expect for it to be dark at that time. Longer periods of light are decreasing the amount and quality of sleep we get (particularly night-shift workers), and those have significant detrimental public health consequences including increased risk of cancer.[1 and references therein] Turning off or dimming the lights at night—especially blue light and light in the bedroom—could help us sleep better and be healthier for it. Minimizing the number of people who are working at all hours of the night and thus exposed to the health risks of doing so would also be good, both from a moral and economic perspective.
Finally, it was made clear throughout that the point here isn’t to turn off all the lights and go back to the stone age, but rather to be thoughtful and deliberate about our outdoor lighting. Making light fixtures which put light where it should go (i.e. down on the ground, not out to the sides or up) and using them only when needed is fairly simple. How much light is really needed at a car dealership, ice rink, or empty parking lot in the middle of the night? Gas stations are often extremely brightly lit, yet most of that light isn’t needed to pump gas or wash the bugs off the windshield. In fact, pulling out of a bright gas station at night can be dangerous since your eyes will have adjusted to the brighter environment and it will take a few minutes for them to dilate again and bring your vision back to its optimum level.
Supposing I turn off my 60 W worth of porch lights (sadly not the dark-sky friendly type) for an average of 10 hours/day year round (3650 h), that reduces my electricity consumption by 219 kWh (780 MJ). At a residential electric rate of $0.08/kWh, that translates to a savings of $17.52 annually, as well as a CO2 savings of 150 kg (3400 moles). It also makes my bedroom darker.
I went outside one night recently when it was clear (albeit humid). I have an urban view, and can only see ~25% of the sky. From my deck, I counted twenty stars. That’s right, I could only see 20 stars. Extrapolating for the full-sky view gets me up to 80, and if we want to be generous we could round that to 100. Compare that to the dark(ish) sky pictured above, and you can see that there’s really a huge difference. In this neighborhood, too, there’s enough stray light running around (even in the summer when leaves block it) that turning off my outside lights isn’t making it hard to get around.
Night can be a pretty neat time. In college, I would occasionally go cross-country skiing at night. Sure, I would have a headlamp with me, but on a clear night I typically didn’t use it. Even cloudy nights, thanks to some local light pollution, were easy to ski without the aid of the headlamp. Being outside at night in the crisp, quiet solitude of a snowy winter was amazing. It’s part of what I missed while in graduate school in a bright, noisy city where it never snows.
After reading this book, I’m looking forward to the Heard Island expedition even more, because the southern ocean, like Antarctica, is home to pristine skies free from artificial lights. Of course, unlike Antarctica, the likely sky condition is mostly cloudy or cloudy, so getting a clear night may be very rare. That will only serve to make the moment more special, if and when it happens. I will bring a camera, and I will try to get a picture of such an event. But that picture will be but a still, lifeless version of the magic at Heard Island.