September storm brings hot weather and warning of increased tropical storm activity to Aleutians
A mid-September storm caused major damage in parts of Western Alaska. In Unalaska though, it brought strangely warm temperatures and a warning sign about future storm activity in the region.
Wreckage from the historic storm spans about 1,000 miles of coastline from the Lower Kuskokwim area, up north to the Norton Sound region. Flooding and strong winds caused power outages, road and home damage and destroyed subsistence harvests and the means to replace those.
While Unalaska was preparing for similar conditions and possible devastation, locals got lucky as the storm passed further west, near Shemya Island.
Rick Thoman, a climate specialist at the University of Alaska Fairbanks, said the high seas and strong winds were the remnants of Typhoon Merbok. And while they missed the Eastern Aleutians, they did push subtropical air into the region.
“So the amazing, amazing warm temperatures that we saw across the region ahead of this, 70 degrees at 10 o'clock at night in Unalaska, must be extremely rare,” he said.
The National Weather Service recorded temperatures of more than 72 degrees in Unalaska around Sept. 15. And while the university’s records on temperatures in the region aren’t complete, that kind of heat in mid-September is very unusual, Thoman said.
But, he said storms like this are known for bringing in oddly warm weather and with that, they can also bring birds that don’t normally visit the region.
“When we get storms, unusually strong or coming from unusual directions, sometimes we do see bird species show up that are way out of their range, basically driven or have come along with the storms,” Thoman said. “So I would not be surprised to see bird species that just simply haven't been seen before or only very rarely seen in the Eastern Aleutians.”
Despite a lot of buzz about unusual avian visitors, local bird watchers haven’t yet reported any notable sightings.
For the Central and Western Aleutians, as well as the Pribilof Islands, Thoman said this storm was a fairly strong one for the time of the year, but nothing too noteworthy.
“Of course it was windy, peak winds over 80 miles an hour at Adak,” Thoman said. “By Adak standards, a breezy day, but nothing too extreme. Temperatures also got very warm out there ahead of the storm, with 68 degrees at Adak.”
Still, it was the strongest September storm recorded over the past 70 years, in terms of lowest pressure in the Bering Sea, he said.
Typically, the waters where this storm formed are too cold to create tropical storms, according to Thoman.
“Ocean temperatures have been extremely warm in this area all summer long,” he said. “So even though 2,500 miles south, southwest of Attu seems like a long way away, that's of course much closer than where typhoons that affect Alaska usually come from.”
On its path north, Thoman said Merbok encountered the warmest water temperatures recorded for the region in the past 100 years or so. With overall ocean temperatures rising, chances of tropical cyclones forming in these areas will increase, he said.
“In our warming environment, and especially warming oceans, over the coming years and decades, we are probably going to see more tropical storm activity in the area, south of the Western Aleutians, than we did in the past,” Thoman explained.
Most of those storms won’t become record breaking like this recent one, he said. But the potential of that happening will increase.
The National Weather Service has issued a high wind warning for the Western Aleutians starting at noon on Sept. 29. Remnants of Typhoon Kulap are expected to hit the Western Bering Sea and Aleutians, with the highest winds expected near Attu and Shemya on Friday morning. Sustained winds of around 60 to 80 mph are expected.