Starting in late May, the sun officially stopped setting in Coldfoot. Instead, the sun gets lower and lower in the sky as it travels from its highest point in the south, swinging around to the west, and finally reaching its lowest point in the north, just above the horizon at local midnight. Then it creeps back up again as it continues its circle around the sky to the east, and back to highest point in the south at local noon.
However, Coldfoot sits in the valley of the Middle Fork of the Koyukuk River, surrounded by low mountains on all sides. From down here, the sun does pass behind the mountains to the west and north as the evening and night pass by, casting us in shadow, leaving the northern sky as red as sunset (and sunrise), and keeping the mountaintops shining like monumental lighthouses.
As we get closer to summer solstice, June 21st or so, the "midnight sun" will remain higher and higher in the sky, though I am not sure it will ever clear our northern mountains. Which means I have a new mission, to hike to the top of one of our hills by midnight between now and early July, when the sun will begin to set again in the north. Then I'll take a picture of myself and a timepiece showing midnight (you'll have to trust me, I guess) in full sunshine.
The changes in light throughout the year are responsible for everything that makes this region different from the lower 48. After the sun begins to set again, it will drop lower and lower toward the horizon at noon each day until early December, when it will cease to rise. Direct sunlight will then be a thing of memory until late January or so. Each day will receive a touch more sunlight until spring equinox, when the ground will see 12 hours of sun and 12 hours of darkness, just like everywhere else on Earth. And by summer the cycle will repeat.
Year-round, the Arctic receives exactly the same amount of direct sunlight as anywhere else on Earth. But here, the sunlight hours are concentrated in the late spring and early summer, and vanish in winter. The effects on the landscape, plant and animal life, and weather are extraordinary.
In winter, life in the Arctic all but shuts down. Temperatures routinely drop to -40 degrees Fahrenheit throughout the interior of Alaska, and can get even colder. Most animals migrate south, hibernate, or literally freeze solid in the case of the wood frog. Many insects and a few mammals have proteins in their cells that lower the freezing point of water in their bodies, allowing them to withstand internal temperatures below 32 degrees F. Squirrels, lemmings, foxes, and some birds remain active in winter, eating from caches tucked away in warmer months or hunting the small mammals active below the snow.
What little light comes in winter is probably not usable by plants, as they, too, hibernate or freeze until warmer weather. Moose, caribou, Dall sheep, and muskox all survive the winter by grazing from plants buried under snow. Unusual freezing rain showers in recent years have caused many caribou and sheep in the region to die when they couldn't break through the ice on the ground to feed. Life here is tenuous.
When the sun returns, life explodes. The snow from winter finally melts, saturating the soil, turning the plains into bogs. Creeks and rivers flood their banks as snowmelt pours down the mountains. Plants go into overdrive, producing leaves, flowers, and seeds as quickly as they can, while they can. Mammals take advantage of the glut of food available, as do many more species of insects than you might expect. Fish, spiders, shrews, other insects, and birds in turn take advantage of the explosion of invertebrate life. Many, many species of bird from throughout the United States and parts beyond flock to Alaska's interior, coasts, and North Slope for the bounty of food and relative safety from predators. The lakes between the Brooks Range and Arctic Ocean can be a birder's paradise for a couple months.
Trees actually grow differently here to capture the sunlight that never comes from above, but from all cardinal directions instead. Black spruce, the most common tree here, often grows bushier branches near the top, and branches remain rather scraggly lower down.
The sun dominates the summer sky. Since May 10th, I've seen only one celestial object aside from the sun or moon, and that was Venus. I've been up as late as necessary to see that no stars have emerged since I got to Coldfoot. No aurora, nothing. Even the moon is illusory. Either it's in a less-than-half moon phase, and remains close to the sun in the sky, rendering it difficult to see, or it's in a more-than-half moon phase, causing it to spend more time below the mountains and the horizon, just like the sun in winter. I saw a full moon last week, but I don't think it will be possible to see the next one. So close to the summer solstice, it will move through the sky just like the sun on winter solstice, which is to say: not at all.
Since the sky never gets truly dark, it's difficult for me to use the word "night" with sincerity up here. It's nice when I get up in the middle of the night to run to the outhouse, no flashlight necessary. It's not so nice when I'm trying to sleep and I have to cover my window with curtains, a towel, and a shirt on a wire hanger (and then I can't wake up easily in the morning with the room so dark). And when we watch a movie at the visitor center that ends after midnight, there's always a moment when I look outside again and think, "oh, it's still light out," as if we had just gotten out of a matinee.
Those who have spent winters here abhor the thought of covering up a window and blocking out sunlight. I've heard of and read about the malaise that sets in during the dark, cold winter, as people wait impatiently for the sun to rise for the first time in weeks or months. From that point of view, sunlight is a blessing, never to be taken for granted again, and locals seem to relish spending as much time as possible outdoors in the summer months, and whither if forced to spend too much time in an office.
As the summer goes by, everything living up here will be making the most of the warm weather and abundant food, from caribou to construction crews. Animals need calories in their bodies or stored in caches underground to migrate, hibernate, or eat throughout the winter. Plants grow as much they can, but never reach the heights or girths of their southern relatives.
Life here seems impossible in the winter, and it all depends on the summer.
Stay in the light.