By Kristin Knight Pace for Frontier Scientists
The brittle cold of Dead Dog Flats is enough to make my parka crinkle as I ladle out the hot mixture of fat and tripe, chicken protein and kibble. One by one the dogs emerge from their houses and, by the time I have gone through the whole yard, a cloud of steam rises above us like a big, collective breath. All our warmth and exhalations are suspended above and around us, encased like a bubble in the -50 night air. Another day like this goes by and yet another. Too cold to run.
Finally a break in the cabin fever-inducing weather and we are back on the trail, cruising along the Yanert River outside Denali National Park. It is 70 degrees warmer than yesterday – a phenomenon that would be front-page news anywhere but here. The runners glide along hard-packed trail and then, like a slow-motion cartoon strip, we are crawling through turquoise-blue water that gloms onto dog booties and runners, caking my boots and turning them heavy as lead.
Overflow, often a product of extreme drops in temperature over a short period of time, occurs when water flowing beneath river ice seeps up through cracks in the ice. As the ice cover on a river thickens, freezing steadily downward toward the river bed, the space available for water to flow is decreased, causing increased flow velocities and pressure.
Mushers who have trained in a particular area for a long time can tell you nearly exact trail conditions based solely on the weather forecast. Four-time Iditarod champion Jeff King has known the Yanert in its best and worst years. After an unusual November deep freeze – when temperatures plummeted to -50 for a two-week stint – King had a feeling the deep, swift Yanert would be as good as ever. Big and fast Alaskan rivers aren’t usually trustworthy until the later winter months, when deep cold has hovered for weeks at a time and unquestionably solidified the waterways. This year, King was putting in 40-mile days on the mighty Yanert by mid-December.
Despite the convenience of a hundred miles of trails right out the back door, mushing in Dead Dog Flats [so named by one local who noticed that a) it is so much colder in this little pocket than anywhere else and b) there are more dogs per capita in our neighborhood than there are humans] has its challenges. The micro-climate of the Yanert River bottom often plunges thermometers to their breaking points (-60 for the one outside our house) while minutes away the temperature can be 20 or even 40 degrees warmer. Mushers and dogs must adapt to the climate in order to train and race successfully.
The hot and cold of it
“If you’re mushing through areas like river valleys, you’re basically in the coldest place possible,” says Anchorage National Weather Service meteorologist John Papineau.
The colder the air, the heavier it is, so it tends to slowly drain down from higher elevations especially at night, he says.
“Even from a couple hundred feet or sometimes less, that cold air seeps down to lower elevations and fills them up,” he says.
“Everything is harder in extreme cold,” says King. “Therefore we go slower. Feeding dogs more fat and encouraging them to drink more is important.”
Indeed, hydration for both humans and dogs requires much more effort in extremely cold temperatures.
“Dogs are almost as likely to get dehydrated in extreme cold as they are in extremely warm temperatures,” says Chatanika musher Jodi Bailey. “It’s much more difficult to get fluids into them in the extreme cold because you have to first find and then make fluids.”
For Bailey, successful travel in extreme climates is all a matter of preparedness.
“When you’re dancing with Mother Nature, she leads,” Bailey says. “If you have really good, positive goals for yourself that make sense, then you’re a lot better mentally prepared to handle what the weather throws at you. Then your success or failure isn’t based on something out of your control.”
When it comes to putting oneself at the mercy of Mother Nature, few races match the extremes of the thousand-mile Yukon Quest. The Quest trail, which starts and ends in either Fairbanks or Whitehorse in alternating years, travels across four mountain ranges in the deep dark and cold of February. Last year’s Quest proved especially grueling, with only 14 of 25 teams finishing the race. It was there that Bailey, along with fellow mushers Dave Dalton and Mike Ellis, woke up at 3 a.m. to booty their dogs only to realize it was 53 degrees below zero.
“I could’ve gotten sucked into a bad attitude or bad goals,” Bailey says. “I could’ve chosen to be too pushy or to accomplish something unrealistic.” Instead, Bailey looked at the mushers beside her and realized it wasn’t really important to her whether or not she beat them or they beat her.“What was important was learning as much as I could and getting a healthy team to the finish line, because I was a rookie,” she says.
After determining that the teams ahead of them were more than a day away, she and her companions decided to wait until the warmer hours of daylight to continue. “It wasn’t a competitive decision, it wasn’t smart as far as racing, but for a rookie who wanted to accomplish certain things, it was a good decision to make,” she says.
A musher’s decision-making is not the only aspect of dogsled racing affected by climate. If 40-below temperatures can cause boiling water to vaporize instantly when thrown in the air, imagine what they can do to the trail conditions.
“The thing that constantly amazes me is water,” Bailey says. “People not living in arctic conditions think you get below freezing and water freezes, which in theory works.”
But Bailey, along with any musher living in an arctic climate, often finds herself baffled by water’s curious winter ways.
“It’ll be 40 below and all of a sudden I’m looking at a knee-deep water crossing on a little creek that, all season long at 0 to 20 below, has been frozen solid,” she says.
During last year’s Copper Basin 300 race, Bailey faced an open-water crossing that left her negotiating with her lead dog.
“We were both kind of standing there saying, ‘You go first.’ ‘No, you go first.’ We both went through it together,” Bailey says.
The knee-deep water instantly froze a quarter-inch casing around Bailey’s outer layers, but because she dressed in waterproof synthetics, her inner layers remained dry. At the next checkpoint, all the mushers were pulling out their axes to knock the ice off their pants and boots in order to get out of them.
“I looked like the frozen version of the Thing from the Black Lagoon from about the knees down,” she says, laughing. “But what would have happened if my boots had gotten wet? I think most of us have some plan B in the back of our minds.”
With extreme cold and ensuing overflow conditions, mushers must always be prepared to rely on quick and creative backup plans using only the limited gear in their sleds. “When Hans [Gatt] got wet during last year’s Yukon Quest, he made mukluks out of dog coats to put inside his Neos [waterproof overboots],” Bailey says.
“In those conditions you just have to go,” says Eureka musher Brent Sass. “And train in it so much that your dogs don’t even get phased by it. That is the best thing you can do – prepare your dogs.” Sass recalls countless times in the Quest where he’s come across people in overflow and, naturally, the dogs bog down a bit. Now the musher is standing in six to eight inches of water, dragging his or her dogs through.
“If you can go through it without stopping, you don’t get wet and you don’t have to deal with it,” he says. “But most people don’t see that type of thing that much in training, and I happen to train in a place where we run into it on a daily basis. We can’t avoid it. I know if I’m getting ready to hook up and it’s been 0 or -10 for a long amount of time and then the temperature plummets to 40 or 50 below, I’m probably going to run into it out there.”
But what about the opposite, when temperatures rise to above freezing?
For Bailey, last year’s Kobuk 440 was very warm. The race trails between the village communities on the coast are oftentimes their major roadways, so trails that are normally super hard and well set-up can, in warmer temperatures, disintegrate with every team that passes until they’re the consistency of mashed potatoes.
“That can be kind of demoralizing because it slows you down a bit and dogs tend to run slower in the heat,” Bailey says.
Sass recalls starting the Yukon Quest one year in Fairbanks at nearly 60 below zero.
“By the time we got to Dawson, the temp was above zero and when we finished in Whitehorse it was 40 above,” he says.
In a matter of nine or 10 days, the temperature had changed 100 degrees. But that’s not something Sass hasn’t seen before. In fact, while training in Eureka, it’s not unusual for Sass to wake up to 40 below and, four or five hours later, after the wind picks up, happen on 10 above.
These extreme temperature swings are a product of inversion, says meteorologist Papineau. During these conditions, the air is colder at the surface than it is at, say, 2,000 feet, where it can often be 10 to 30 degrees warmer.
“At times when there’s a transition, like winds, there can be a huge warm-up within hours,” he says. “The inversion breaks down, the wind mixes in the warmer air from above and all of a sudden it’s 30 to 40 degrees above zero.”
This phenomenon occurs all throughout Alaska and all over the world, he says. As far as he knows, no research has been done to catalogue whether these types of events are increasing or decreasing and whether that increase or decrease could be a product of broader climate change.
“Dogs can’t change their coats and long johns”
Coming off last year’s extremely frigid Yukon Quest and a week later going into one of the warmer Iditarods on record was a tough transition for mushers like Bailey.
“There’s even video of me going, ‘Yeah, not liking the warm. Not liking the warm,” she jokes.
But what would the dogs say about it?
“Extreme temperatures either hot or cold can negatively affect a dog’s performance,” says Dr. Jayne Hempstead, dog musher and owner of Cantwell Veterinary Services. “We humans adapt to changing temperatures by changing what and how much we wear. We can also build a fire or sometimes seek shelter. Dogs have to adapt to extreme temperature changes in other ways, because they obviously can’t change their coats and long johns.”
According to scientist Ted Greenlee’s 1971 paper, Temperature Adaptation in Northern Dogs, the thick, double-layer of fur that insulates Alaskan Huskies from extreme cold also protects them from overheating in very warm temperatures. As he puts it, “It is much easier to air-condition a well insulated home than it is to air-condition one that is not insulated. In the case of the animal, the only requirement is that there be some relatively efficient mechanism that the animal can turn on to dissipate his own heat.”
Anyone who has seen a team of huskies beat feet down the trail with lolling tongues knows that panting is quite an efficient heat-releasing mechanism. Greenlee concludes that animals with an insulating mechanism (thick double coat) coupled with a heat-releasing mechanism (panting) can maintain their body temperatures even with big changes in outside temperature. Animals that have not adapted this type of mechanism, he writes, such as short-haired dogs, are very susceptible to an abnormal increase in the outside temperature as compared with what he is used to and thus are more susceptible to heat stroke.
“Dogs primarily release body heat by panting, however they are able to sweat through their feet as well,” says Hempstead. “If a dog is bootied, that can inhibit the ability to release heat through their feet and can be an issue if the temperatures are high – say 20 above or higher.”
The other method of heat control employed by northern dogs is a wonder of adaptation. One could ponder, as his or her hands and feet become tingly and numb and quite susceptible to frost injury in extreme cold, what happens with dogs in these situations. As we humans are not well-insulated, our bodies, in order to protect our vital organs, will shut off blood supply to the feet and hands. For a dog in -60 or -70 temperatures, his body will do no such thing. Writes Greenlee, “Instead of stopping the blood supply to the extremities so the blood does not become chilled, what occurs is that the warm, oxygen-carrying arterial blood going into the limb runs right next to the cold, unoxygenated blood leaving the limb. Since they are right next to each other, the warm blood gives up its heat to the cold blood, preventing the loss of this heat as it gets down to the exposed part of the dog’s foot. The oxygenated blood can get to the vital parts of the foot to maintain their nutrition, but at the same time does not allow a loss of body heat to the cold air.”
“Dogs will typically burn more calories the colder the temperature, simply to keep their body heat steady,” says Hempstead. “While sled dogs are working, that isn’t usually an issue. However at rest, it will take much more energy to maintain a normal body temperature in an extremely cold environment.”
According to Hempstead, smaller dogs generally require more energy to stay warm and of course dogs with short or less dense coats will expend more energy to stay warm than their thicker-coated teammates.
“Fortunately, studies have shown that dogs are capable of adapting to burning dietary fat similar to how humans metabolize carbohydrates,” she says.
In humans, fat that is consumed must first be stored as either glycogen or body fat before the body can use it for energy. The dog has the capability of “learning” how to use fat directly out of the bloodstream. And since fat has about two and a half times as many calories as carbohydrates or protein, that ability to utilize fat is so critical in extremely cold temperatures.
“During periods of high activity such as racing, combined with cold temperatures, a dog simply could not consume enough carbohydrates or protein to meet its calorie demand,” Hempstead says.
Another thing mushers must consider is that snow temperature changes much slower than air temperature.
“Sometimes, like just recently, it may be -35 for several days and then suddenly warm up to 20 above,” says Hempstead. “The snow is still cold and abrasive, but the air temperature is ‘hot’ for a sled dog.”
In this instance, putting booties on the dogs may contribute to overheating, but allowing them to go barefoot may cause sore feet.
“It takes experience and good judgment to make the right decisions consistently,” she says. “If we expect our dogs to keep working for us in spite of the weather, we must be prepared for everything that Mother Nature dishes out to us.”
“Climate and mushing? They go hand in hand,” says Sass. “That’s what makes this sport so exciting. Mother Nature is what drives this entire thing. We have zero control over weather. We can control everything else, we can drive our dogs to the best of our ability, but Mother Nature is going to throw everything at us and it’s about how we adapt as mushers.”
Besides, adds Sass, “change and fluctuation are a part of this sport. It would be pretty boring if it was always 10 below and sunny out.”
Back on the Yanert, my sled passes through a wall of cold. It is such a quick temperature change that I question my perception, but then I see it: wisps of frost outlining every whisker and eyelash, spreading along the faces of my dogs and onto their sides and backs like fine, white paint; winter’s fickle ambience slipping over us like a glove.
Kristin Knight Pace is a dog musher, backcountry ranger and freelance writer from Denali National Park, Alaska.