Low snow drives Iditarod north for third time

For only the third time since its inception in 1974, Alaska’s famous Iditarod Trail Sled Dog Race kicked off in Fairbanks—250 miles north of the traditional start in the southern coastal city of Anchorage. Iditarod Trail Committee officials announced the decision in February, citing “poor conditions of critical trail areas in the Alaska Range,” as the reason behind the shift north.

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Each time the race has been forced to re-route—the other two years were 2003 and 2015—it was due to lack of snow and unfrozen rivers, streams, and ponds in the low-elevation passes of the Alaska Mountain Range.  Earlier this year, local news outlets reported low snow in Rainy Pass and the Dalzell Gorge, a “notoriously perilous stretch” of the traditional trail located on the north side of the Alaska Range.

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It’s not a coincidence that all three re-routes of the Iditarod have occurred in the more recent decades of the race’s history. The December-February average temperature for the state as a whole is warming by 4.2 degrees F per century.

Winter temperatures in Alaska’s central interior, which includes the northern passes of the Alaska Range, are warming at a rate of 5.2 degrees F per century. To put that into perspective: that’s more than double the rate of winter warming in the lower 48 states (2.2 degrees F/century).

Winter (December-February) temperature in U.S. Climate Division 3 (central interior region) since 1925 (dark blue line) along with the warming trend (dotted blue line). NOAA Climate.gov graph, based on data from NCEI’s Climate at a Glance.

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Record warm temperatures were what pushed the race northward in 2003 and 2015—the state’s 3rd warmest and 5th warmest winters on record, respectively. Even 2014, which caused the mushers trouble in Rainy Pass, was the state’s 8th warmest winter on record. But that wasn’t the case this year. This winter has been climate “normal” for much of Alaska; it was only the 32nd warmest winter since records began. But according to Rick Thoman, climate services director for the Alaska region of the National Weather Service, some finicky upper-level wind patterns shut the Rainy Pass area out of the snow bounty seen elsewhere in the state.

Even if this winter was an average one for Alaska, it followed a record-shattering year for the state. In 2016, many Alaskan communities recorded their highest average temperatures ever: including the traditional Iditarod bookends of Anchorage and Nome. Anchorage’s average temperature in 2016 was a record-breaking 4.4 degrees F above normal and Nome’s was a record-breaking 5.1 degrees F above normal.

As climatologist Deke Arndt has blogged about before, one global warming rule of thumb is that colder places are generally warming faster than already warm places. Alaska is our nation’s poster child for that rule, thanks to the process of “Arctic amplification” of climate change. As temperatures rise and sea ice and snow melt, the darker water and land surfaces reflect less incoming sunlight, accelerating warming.

The impacts extend to things more consequential than the Iditarod. Permafrost is thawing and collapsing, undermining roads and other infrastructure--even whole towns. Sea ice declines have left coastlines exposed to battering waves and severe erosion. Insect outbreaks and fires are becoming more extensive. The behavior of animals that sustain the traditional hunting patterns of native peoples is changing. Iditarod aside, Alaska is racing toward a very different climate future.