Arctic climate change may have fed Hurricane Harvey

Only thing missing—palm trees: Gjoa Haven, one of Nunavut’s hot spots, this August, under sunny, warm skies, as shot by Natta Summerky, with the C3 Canada 150 voyage which stopped in the western Nunavut community on the Aug. 24 and Aug. 25. (PHOTO COURTESY OF C3)

(Updated Sept. 6)

Last month, you could have seen swimmers in the western Nunavut town of Cambridge Bay diving into the Arctic Ocean to cool off—the month of August in Nunavut proved to be an extreme record-breaker with respect to high temperatures and low precipitation.

So, when Hurricane Harvey dumped about a metre of water on Texas last week—or again, this week, when powerful Hurricane Irma moved across the Caribbean, causing devastation in its path, Nunavummiut might not have thought about the link between these huge disasters to the south and warm weather in the North, which came as a welcome surprise to those who enjoy boating or heading out on the land.

But Charles Greene, a professor of earth and atmospheric science at Cornell University, who has called the Arctic a “wild card in the weather,” suggested most recently that Arctic heat may have contributed to the intensity and length of Hurricane Harvey.

That’s because, with the increased warming of the Arctic, temperature differences between the Arctic and mid-latitudes are reduced, Greene said in an email to Nunatsiaq News.

These temperature differences are what drive winds, and when these differences are reduced, the winds slow down.

“When the jet stream slows down, it begins to meander more, and it can often stall in place and form high-pressure atmospheric blocks… What truly made Harvey a catastrophic hurricane was in getting locked in place between two high-pressure blocks,” Greene said.

If future studies can demonstrate that this could be associated with Arctic warmth, “then the most destructive aspect of Hurricane Harvey can be linked to climate change,” Greene said.

Meanwhile, when Hurricane Harvey gathered strength over the Caribbean Sea in August, Nunavut’s Kivalliq region remained dry—and unusually so.

That’s what prompted Gordy Kidlapik of Arviat to post on Twitter about what he was seeing.

This is the lowest I seen Tub Pond, where we wash trucks and fish tubs. I also seen a big brown water beetle, like in Churchill. 1st time to pic.twitter.com/vG7Czq47QD

— Gordy Kidlapik (@Ingutaq) August 30, 2017

Data provided to Nunatsiaq News by Patrick Duplessis, a graduate student at Dalhousie University and an avid weather-watcher, confirms Kidlapik’s observations.

The precipitation drop in Arviat was “pretty dramatic” in 2017, breaking existing records, Duplessis said: Arviat’s August rainfall only amounted to 1.1 millilitres—that’s more than 50 times less than the normal rainfall of 56 mm.

To find the previous driest summer in Arviat since the 1970s, you have to go back to 1991 when 14.6 mm of rain fell.

Baker Lake was also extremely dry, with five mm of rain—far lower than the normal of amount 51.2 mm, and the driest since 1949 when 2.5 mm of rain fell.

Also in Rankin Inlet only 7.6 mm of rain fell, far less than the normal 57.2 mm.

In the central Nunavut hub, “there are no drier Augusts in continuous records back to 1981,” Duplessis said— and only 1954, with 4.6 mm, was drier in Rankin Inlet.

But there were also plenty of heat records broken throughout Nunavut in August.

The heat “came from west and sat on Nunavut,” said Duplessis, who noted that, for some weather stations, the high temperatures recorded were “very extreme,” particularly during the third week of August.

The Aug. 24, the 25 C temperature for Baker Lake broke the standing 21.1 C record-high temperature for that date set back in 1946.

Also on Aug. 24, the 25.7 C temperature for Kugluktuk broke the long-time record of 21.1 C for that set in 1954.

In Cambridge Bay, the temperature of 18.5 C on Aug. 23 broke the previous high of 18.2 C recorded for that date in 2006— and that came after a heat wave earlier in August, which saw other high temperature records broken in Cambridge Bay and a record-breaking high of 33.5 C set Aug. 12 in Bathurst Inlet.

A sample of other record-breaking high temperatures set in August, which Duplessis furnished, include:

• Naujaat, Aug. 23: 16.3 C, breaking the record of 14 C from 1989;

• Kugaaruk, Aug. 23: 21.1 C, breaking the recond of 17 C in 2006;

• Rankin Inlet, Aug. 23: 18.6 C, breaking the record of 18.2 C in 2012;

• Coral Harbour, Aug. 23: 18.6 C, breaking the old record of 16.7 C from 1949;

• Gjoa Haven, Aug. 24: 16 C, breaking the record of 12 C from 1989;

• Taloyoak, Aug. 24: 16.4, breaking the record of 15.6 C from 1989;

• Chesterfield Inlet, Aug 24: 21.2 C, breaking the record of 18 C from 1991;

• Arviat, Aug. 26: 22.4 C, breaking the old record of 18 C from 1999; and,

• Hall Beach, Aug. 26: 17 C, breaking record of 11.8 C from 1989.

For the first time in 10 years, Iqaluit did not reach 20 C this summer, with its peak temperature reaching just 19.5 C, the lowest summer high temperature recorded since 1999, Duplessis said.

But, even so, Iqaluit’s average temperature for August, 7.9 C , was the warmest since 2016 (8.8 C), mainly due to some record-breaking warm nights.

The hotter-than-usual August means that average temperatures for the month in many communities showed big differences—or anomalies— from the norm. In Kugluktuk, the temperatures were 4.4 C higher than usual in August and the average temperature for the month came in at 13.4 C—the warmest average August temperature there since 1954 when the average for that month sat at 13.5 C.

Cambridge Bay and Gjoa Haven also saw warmer-than average-temperatures in August.

In the west, these warmer temperatures are likely to continue into September, Duplessis said, mainly due to warmer ocean temperatures—although cold has already started to build up in the High Arctic, with the Sept. 2 low of minus 6.4 C the coldest on record at Alert, beating minus 5.2 C in 1978.

On this map prepared by Patrick Duplessis of Dalhousie University, you can see how much higher or lower the temperatures were overall in August in Nunavut. Although Iqaluit never saw a day above 19.5 C the difference from the norm—the temperature anomalies—actually showed an average temperature for the month which was .8 C more than usual.