For the first time, Alaska’s statewide spring temperature averaged 32 degrees. That may sound cold, but no previous spring in Alaska’s 91-year climate record has ever been so warm, or even come close. The previous warmest spring, in 1998, averaged 30 degrees.
This spring’s temperature straddling the freezing-melting threshold was a staggering eight degrees above the long-term average — a much more solid 24 degrees.
Unusual if not record-setting warmth was ubiquitous across the state.
— NWS Alaska Region (@NWSAlaska) June 8, 2016
During May, due to an upside-down weather pattern, it was sometimes warmer in such cities as Anchorage and Fairbanks than it was in Washington and New York.
At the northernmost point in the United States, Barrow Observatory, all of the snow had melted as of May 13, the earliest in 73 years of record-keeping, NOAA said. The snowmelt was a full 10 days ahead of the previous earliest instance, in 2002.
The Alaska Dispatch News noted some other indicators of the unprecedented spring warmth, including:
* Record early river ice breakup of the Yukon River at Dawson (April 23) and the Kuskokwim River at Bethel (April 20)
* The earliest green-up on record in Fairbanks, when leaves emerged on tree branches on April 26
Arctic sea ice, bordering Alaska’s northern periphery, reached its lowest extent on record in May.
The record-setting spring followed Alaska’s warmest winter on record, in which the temperature was more than 11 degrees above the long-term average.
Most locations in Alaska with a long-standing climate record are having their warmest year on record, so far.
— Brian Brettschneider (@Climatologist49) May 31, 2016
The warmth has been remarkable for both its intensity and endurance. In many locations, temperatures have remained well above average for long periods with little interruption since last fall.
Forecasters have had an easy time predicting Alaska’s temperatures, forecasting above-normal temperatures in long-lead outlooks almost without exception.
— Brian Brettschneider (@Climatologist49) April 20, 2016
This year’s strong El Niño event, and the associated warmth of the Pacific Ocean, is probably partly to blame for the warmth, along with the cyclical Pacific Decadal Oscillation – which is in its warm phase.
The warmth is also occurring against a backdrop of temperatures that have been trending upward due to the accumulation of greenhouse gases in the atmosphere.