When winter temperatures in Alaska's largest city rise, Mike Abbott has reason to sweat.
Abbott, chief of operations for the Anchorage School District, mobilizes the forces that decide whether weather is bad enough to cancel school, a process that starts with field reports streaming in at 3 a.m. on questionable days. In Anchorage, cold and snow are not weather problems for local schools. Rain is the enemy.
For the past decade, almost all of the district's weather-related school closures have been caused by winter rain that turns roadways into toboggan runs. Unlike snow, which Anchorage maintenance crews handily plow away and which motorists can navigate, albeit slowly, the thick ice formed by winter rain defies a quick solution. Rain forced district-wide closures on Dec. 5, among other Anchorage disruptions. Last week, a period of pouring rainfall turned out to be even too warm for significant formation of ice, so the school district wound up escaping any closures. But Abbott had another rain-related headache: too much water rushing into cold pipe systems.
"I have lived in Anchorage for 40 years, and I never remember events like these for the first 30 of them," Abbott said. "This is what Anchorage winters are now."
Rain and ice closes school
Other parts of Alaska, including areas well to the north, are coping with similar winter rain problems.
In Fairbanks, where some hardy residents scoff at winter temperatures that sink below minus 40 degrees F, rain last week forced a temporary closure of the local international airport and another day of closures for schools, which already had closed for three days in November because of icy rain. These winter rain school closures have been regular occurrences since 2002, and they include the "Icepocalypse" of November 2010, a major weather event that sent rain as far north as Barrow and created a thick layer of ice in Fairbanks that lasted on some streets for the entire winter.
Rain and the ice it created forced school closures last week in the Delta-Greely School District southeast of Fairbanks, where winters are normally so cold that there is a popular children's book, "Recess at 20 Below," set in that location. Schools in Bethel closed in early December for icy rain conditions considered odd and dangerous by residents accustomed to winter snow, and the Kuskokwim 300 sled dog race, which starts and finishes in Bethel, battled wet and warm conditions.
Driving rain on top of snow creates hazardous avalanche conditions, too, triggering slides like those that cut off road access to Valdez. As of Tuesday, warm, rainy weather had forced six days of closures in the past two weeks at Alyeska Resort, and the ski area's mountain website gave a grim report about the closure continuing until at least Thursday. "Along with the rest of Southcentral Alaska, Alyeska Resort has been dealing with unseasonably warm temperatures for the past few weeks. The combination of a saturated, shallow snowpack and the warm temperatures have made for unstable conditions at the ski area," Tuesday's snow report said.
Lack of sea ice implicated
Here's what climate scientists say about winter rain in Alaska and other high-latitude areas: Get used to it.
The International Panel on Climate Change has warned for years that as the Arctic warms, an increasing proportion of high-latitude precipitation will come down as rain rather than snow. Such predictions extend to Alaska specifically, as detailed in a University of Alaska Fairbanks study published last year.
The weather patterns that last month brought Norway its biggest December rainfall totals since 1975 and forced some hibernating bears out of their wet dens in Finland are expected to become more prevalent in the future in Norway, Finland and Sweden, according to the Organization for Economic Cooperation and Development.
Over the long term, winters are getting warmer in the higher latitudes, meaning more of the precipitation will be in droplet form, not flakes, said John Walsh, chief scientist at UAF's International Arctic Research Center. "It would be snow in the old days. But now it's rain," said Walsh, interviewed on a rainy January day in Fairbanks when the temperature hit 42 degrees. The icy messes will continue as well because the gradual warming will not be enough to change the frozen condition of the ground, he said. "Freezing rain on the surface will likely be more common, gradually, as the weather warms," he said.
Lack of sea ice is implicated in some of the far-north winter rainfall.
Bigger areas of open water are exposed in the fall, the period of minimum ice coverage. That means Arctic water, which absorbs solar heat throughout the summer, has more time and power to return heat and moisture to the atmosphere, climate scientists say. The vented moisture produces late-fall or early winter rain, often in heavy downpours. "This is all a very expected part of global warming," said Jennifer Francis, a research professor at Rutgers University.
But at this late point in the winter, is Arctic warming and reduced sea ice cover responsible for the "polar vortex" gripping the Lower 48 in cold, Alaska-like weather and giving Alaska moderate southern weather? That is a subject of vigorous scientific debate.
One theory, put forth by Francis and others, offers this explanation: The rapid warming of the Arctic is reducing the temperature differential that normally separates northern and southern weather. That temperature differential helps control the jet stream that usually pushes weather patterns west to east; a weakened differential causes the jet stream to meander in a north-south direction, bringing warm weather north and pulling cold weather south. "When the jet stream gets into the high Arctic, you tend to get both kinds of extremes," she said.
The argument "makes good physical sense," Walsh said, but more years of data are needed to make a distinction between weather fluctuations and a particular climate trend.
Ice breaking snow plow
In Fairbanks, for example, rainy winters are not an entirely new phenomenon. Rick Thoman, climate science and services manager for the National Weather Service in Fairbanks, has combed through a century's worth of records and documented a pattern. While big rain events have been seen in the past 15 winters, he said, there were similar stretches in the 1920s and 1930s, according to his studies. "That's an observation. That's not an explanation of why it's happening," he said. More time and data is needed -- perhaps another 10 years of observations -- to make any conclusions about whether rainy weather is the long-term trend for Fairbanks winters, he said.
Northerners living with winter rain are, for now, focused on short-term responses.
The Alaska Department of Transportation and Public Facilities, pleased with results from experiments with a Finnish-made ice-breaking snow plow, has put in an order for two more of the vehicles, department spokeswoman Hannah Blankenship said. When officials imported DOT's first Raiko icebreaker from Finland and put it to work earlier this winter on icy roads, Alaska became the first U.S. state to have its own transportation department use one of the ice-grinding devices, she said. The Raiko icebreaker uses a set of spikes on a wide roller to break up ice sheets and transform them into granular surfaces.
Warm-weather woes might force alterations to important sports events.
In Canada's Yukon Territory, where sled dog racers have bemoaned the so-called "Pineapple Express" that brought rainy southern weather north, organizers of the Yukon Quest International Sled Dog Race have already announced a course change and other potential alterations to cope with the soggy conditions.
In northern Europe, where warm and wet conditions have prevailed for much of the winter, ski race organizers have canceled events, scrapped long-distance World Cup cross-country contests in favor of sprints and dumped trucked-in snow to create courses on otherwise-bare ground or ski jumps.
German ski cartoonist Thomas Zipfel took notice and jokingly suggested a new Nordic sports event suited to the new Nordic conditions -- a combined ski racing and mushroom-collecting contest.
Contact Yereth Rosen at yereth(at)alaskadispatch.com