We had an interesting warm spell over the past week, here in Interior Alaska, so much so, that we feel the need to examine it in some depth. 
Warm spells occur here every winter of course, and give us a welcome break from temperatures of -20 to -45C. This winter has been quite mild, our cold spells have been very short, only 3-5 days in duration, generally, separated by two to three week periods of much milder conditions, brought on by a weather pattern, like this, to the left. When a strong high pressure ridge builds north along the west coast of North America, and mild subtropical air flows north, all the way through Alaska to the Arctic.
This chart, above, shows a strong ridge that did just that, over the past 10 days, and brought very mild air north over Alaska. On Friday and Saturday, 19-20 February, surface temperatures reached 8-14C (46-58F!) over much of Interior Alaska, including here at the Chena Ridge Research Center, where we reached 8C. These temperatures are 15-20C (27-36F) above average for this time of year. This chart, to the right, is the temperature and wind-profile, from the twice-daily radiosonde balloon release, in Fairbanks, from friday afternoon, 20 Feb. These are done in thousands of places world-wide, at 00 and 1200 Greenwhich Mean Time. These "soundings" provide the backbone of the data set for the supercomputer-based weather forecast models, which provide meteorologists with forecast charts for different atmospheric parameters and levels, going out as far as 10 days ahead (though accuracy rapidly diminishes after 3 days, and much more so after day 5). What the above upper-air profile is showing, is a very pronounced bubble of above-freezing air in the lower atmosphere here over Interior Alaska. The thick black line, on the left, is the temperature, measured by the balloon, as it ascends. You can see that it remains to the right of the light blue 0C line, up to about 2200 metres (7200 ft.). Meaning, that the free-air freezing level at this time, was around 2200 metres! This is unprecendented, in my experience, forecasting here in Fairbanks. And why, on this day, surface temperatures were so warm. This atmospheric "sounding", in fact, looks more like one we would see in May, than mid-February. The black temperature line, decreasing with height, shows a sharp break at 11,300 metres. This marks the top of the troposphere, the lower layer of the atmosphere where active weather occurs. This "tropopause" (height where the troposphere transitions into the stratosphere) height of 11,300 metres, is almost 3000 metres higher than average, for this time of year, in Alaska. Meaning, the troposphere is much deeper, because the air-mass is so much warmer, throughout its depth.
What was it about this ridging pattern that made it so warm here? This infrared satellite image from fri. afternoon 19 Feb. tells the story. You can see the clear skies over British Columbia and the Yukon, under the high pressure ridge. Over the Pacific and Gulf of Alaska, two low pressure systems are present. As these lows move north, in the southerly flow on the front side of the ridge, they transport very mild air northward, in their wake, after their passage. And reinforce the mild air. The longer this pattern remains, the warmer the airmass becomes, over Alaska.
Interior Alaska is locked in a drought pattern, caused by frequent occurrences of this pattern, since last spring. The period from last July, to mid Feb., is the fourth driest since accurate precipitation records began, here in Fairbanks (around 1920). Only 11.5 cm of precip. has occurred (of which, only 53 cm of snow has fallen, about a third of average). March and April are typically the driest months in Interior Alaska, so the odds are not in favour of any relief from this. And hence, when our Boreal Forest awakens from it's winter dormancy this May, it will have much less moisture to work with, for new growth and general health. If a dry pattern continues into May, June, and July, another very bad fire season will occur here. We hope this won't happen!
In our last article, while we were discussing the nightmarish environmental conditions produced in China by their embracing of unrestrained Capitalism (in a supposedly Socialistic country!), we mentioned it's pollution travelling across the Pacific, to the western U.S. Well, here's a good article that came out today describing the latest research on that issue.
It seems like we are always at least a week ahead of other sources providing you with insightful and important information, here at the Alaska Progressive Review! Stick with us...
GOING WITH THE (chinook) FLOW II
A.P.R.'s favourite adventure and travel companion, Erik, and I had decided back in Dec., that we would like to ski in, if possible, to the Maclaren lodge, 67km west of Paxson, on the Denali Highway, in mid-February, but only if it was "warm" (above about -15C or so), because we wanted to skate ski, which is faster than classic skiing. The Denali Highway is closed to automobile traffic in winter, unmaintained by the Alaska DOT. But, the Maclaren lodge usually grooms it with a snow-groomer, providing a wide, level track for snowmachiners and skiers. Because there is alot of high-speed snowmachine traffic on the highway, Mattie and Homer had to stay back at the Chena Ridge Research Centre. We didn't want to jeopardise their safety, as sometimes snowmachines can be speeding along at 130-150 kph!
When we saw the warm spell coming together around 08 Feb., we finalised our plans. We'd meet the next fri. night in Paxson, stay the night there, then ski out to Maclaren sat., stay there sun. 2/14, and ski back out monday. Things went according to plan, we spent a nice night in a Denali Highway Cabin http://www.denalihwy.com/, then got up and hit the highway at 0900, on our skate skis.
Unfortunately, I had not called ahead about the highway conditions. After only about a half-km on our skate skis with our 20 kg packs on, we realised, this wasn't doable on the narrow, bumpy track, that wasn't groomed. Had we known, we could have brought our classic skis, and made it in just fine that way, though it would have taken several hours longer.
But, Erik is very resourceful, and forward-thinking. He brought along his little 25 year old Skidoo snowmachine, named Patrick. Very simple mechanically, with a small 300cc or so engine, no gages, and only a pull-start. Yet Patrick always starts on the first pull. So, we went back to Erik's truck, and loaded all our packs and skis onto the back of Patrick, started him up, and headed out. He ran smoothly the whole way. We had to go fairly slowly, with our precarious load, on the sometimes narrow, bumpy, and curved route, only about 35-50 kph.
It was fairly mild at the start, -10C or so, and after about 12km, we had to stop and readjust the load, at this beautiful point, with expansive views of the Alaska Range back to the east and north. I was starting to get a little cold though, mainly because I neglected to bring my insulated glacier pants, since I'd thought we'd be skiing. My knees began to get quite cold.
By the time we got to this point, at the top of Maclaren Summit, about 10 km from the lodge, my knees were numb and I could barely walk. We had to stop a few times to warm up. It was a little colder here, probably -15C or so (+5F). The warmer air aloft hadn't fully mixed down to the surface yet. Still, the view north here to Maclaren glacier, emanating from 4217 metre Mt. Hayes (13,832 ft.) in the distance, was sure beautiful.
We got to the lodge at noon after about a two-hour trip on Patrick, with three stops to warm up and readjust our shifting load of packs and skis. Erik's skillful pilotage of the machine kept us safe and level on the sometimes bumpy track (he used to be an avid snowmachiner many years ago, and it showed). We rushed right into the lodge and warmed up next to the big woodstove to thaw our cold hands, feet, and knees. Maclaren lodge is open year-round. When the highway is open to cars and buses, alot of tourists stop in, and hunters, in the fall, looking to take a caribou from the large Nelchina herd, that roams the vast expanse of open tundra. We had just missed the tail-end of the Denali Double 200 dog-mushing race. Teams departed from Paxson, went down the highway to Cantwell, then back to Paxson. So the staff at the lodge were very tired, from serving the mushers and helping out with the dog teams.
I inquired about the highway grooming situation. It seems their groomer, here, a very expensive and large one, acquired from the Whistler Ski Area in BC (yes, the Whistler, of Olympic fame), is down for the moment mechanically. But, their also isn't really enough snow anyway for it, it needs close to a metre or more of snow depth, and there was only about half that on the highway. We had reserved a little cabin, but were a little taken aback by the fly situation. It was infested with blackflies. I would leave the door open to freeze them out, then sweep them up and throw them outside. But after that, in a few hours, a new batch appeared! Finally I gave up, and we just endured the two nights with them in there. It would require opening up the cabin for a day or two with temperatures of -30C or so, to freeze all of them and their eggs, out of every nook and cranny. 
After warming up and unpacking, a couple hours later, we decided to at least see how skiing would be on the highway from the lodge, without packs on. I put on my skate skis and pushed out just about 13 km west on the highway, then headed back. It was quite bumpy and narrow in sections, so I knew we had made the right decision to snowmachine in. Erik met up with me on my way back to the lodge, and snapped this as I headed up a short hill. Skating is my favourite form of nordic skiing, because you can go so much faster, and further, with less energy expenditure, once your technique evolves, and when conditions are good.
On the way back to the lodge, as the sun began to set, I was rewarded with a view of Mt.Hayes pink in the rays of the setting sun. Had to stop for a picture of that! Sunday the 14th dawned cloudy and cool at the lodge, still only about -15C or so. After a leisurely breakfast and a few hours of reading and relaxation, we decided to run back east up the highway, to Maclaren summit, 10km, and further, if we felt up to it, then back. Since skiing conditions weren't the greatest. Once we got on the valley slope 100 metres or so higher, the warmer chinook winds were blowing, and it felt much warmer.
The Denali Highway is the second highest roadway in Alaska, because of this, Maclaren Summit. The only higher one is on the Dalton Highway (of Ice Road Truckers fame), Atigun Pass, at 1463 m (4800 ft). Running on the loose-packed snow on the highway was extremely taxing, like being on beach sand, so I only ran up 11 km, then turned back. Erik though is used to this, running in Valdez, which gets so much more snow than Fairbanks, so he was able to go out 14 km, before heading back. As you can see here, south of the Denali Highway is a vast expanse of open semi-tundra; swampy country, broken up by hills and low mountain ranges, for over 200 km, until you get to the higher Talkeetna and Chugach mountain ranges, and then the milder, wet coast along the Gulf of Alaska. 
We enjoyed another nice evening in the lodge sun. after being out part of the day. The food there was pretty basic, as you might expect in a place that has no auto traffic for half the year. But not bad, considering. The other guests, 5-10 or so, had all snowmachined in as well, so we talked with them. There is a full bar there, but I was able to discipline myself, and not cut loose too much, though it was tempting. Sunday night, the chinook winds came up in full force through the valley, and shook the cabin, waking me up around 0300. It warmed up to about -2C, so when we packed up for the ride back out to Paxson, at 0900, we knew it would be an easier, more comfortable trip.
This time too, we decided to wear our packs, with both sets of skis strapped to mine, rather than bundle everything up on the small rack behind me. On the way in, my lower back got quite bruised from bumping the metal rack. This way, it was protected, and we didn't have to stop to readjust the load.
It was definitely the way to go. We were both much more comfortable, in the warmer conditions, and my back wasn't getting battered. During our trip back, other snowmachines heading west would sometime zip past us so fast, by the time I noticed them, they had passed! They must have easily been going at least 130 kph! Near Tangle lakes, about 35 km east of Maclaren, we stopped and watched as some of the Nelchina herd of caribou crossed the highway. We saw hundreds of them here in August, 2008, when Mattie and I packed around for a few days north of Maclaren Summit, near Sevenmile Lake. This was the trip when little 20 kg 15 month old Mattie ran off a 150 kg large bull caribou nosing around our camp, unhappy at our presence in "his" area. Before I could stop her, she charged after him, running up and around him, barking. He could have dispatched her with one kick, but fortunately decided to run off. Mattie is not as large, or imposing, as Homer, with his wolfy presence, but our intrepid assistant editor has a strong, courageous heart, and epic endurance.
So, even though we were not able to skate ski in to the Maclaren Lodge, like we had hoped, we had a nice weekend getaway to a beautiful place in the Alaska Range, where few people travel. Had we known beforehand we probably would have brought our classic skis, and skied in to the lodge. Because then we could have skied in to near the Maclaren glacier, here. It pays to call ahead!The mild weather of course, greatly helped our enjoyment of this trip. But we know, it is coming at a price. More frequent mild chinook/southerly flow patterns like this are allowing our more of our permafrost to melt, releasing more CO2 and methane, positive feedbacks to global warming, and not allowing the Arctic sea ice to freeze as thick each winter. Leading to increased melting each summer. Which will lead to ice-free summer conditions in the Arctic Ocean, within a decade. Another positive feedback. Cheers.
