WEATHER NEWS: Strongest storm in decades set to hit Alaska with coastal flooding, high winds
A powerful extratropical cyclone is blasting into the western coast of Alaska — bringing potential perils from a storm surge that threatens to top out at 18 feet and gusts that will reach up to 90 mph.
“This continues to be a dangerous storm as it is producing water levels above higher than any seen over at least 50 years,” the National Weather Service’s Fairbanks office wrote in its Saturday morning forecast discussion. The National Weather Service has issued several warnings to account for a multitude of hurricane-like threats.
As the powerhouse system approached Alaska late Friday and into early Saturday, roaring south-to-southwesterly winds battered the state’s west coast. Through Saturday morning, widespread gusts had reached 45 to 77 mph.
Massive amounts of water, shoved north by the high winds, were sloshing ashore, raising the ocean multiple feet and battering vulnerable coastal communities with severe erosion. The tide gauge in Nome, which is known for being the end point of the famed Iditarod Trail Sled Dog Race, showed water levels more than 7 feet above normal levels early Saturday.
Reports from social media indicated power outages and damage in a number of coastal communities because of the rising waters. In Hooper Bay, a small city on Alaska’s central west coast that is home to 1,375 people, some families were reportedly evacuating their homes because of the flooding.
Just talked to my Aunt. Please, please, PLEASE keep my village of Hooper Bay in your prayers. Flooding is real bad with the storm surge off of the Bering Sea coming in. They’re expecting hurricane force winds this weekend and evacuations of families from their homes are happening
An offshore ocean buoy reported waves at or above 35 feet for 12 hours, peaking at more than 50 feet, while winds gusted over 70 mph for 11 hours.
The storm will stall just offshore the Seward Peninsula over the weekend, continuing to push the Pacific toward Alaska’s vulnerable coastline.
“The duration of the high water is quite a bit longer than we often see, so that will lead to a longer duration of high impact surge and waves pounding the coastline,” Ed Plumb, a senior service hydrologist at the National Weather Service’s Fairbanks office, told The Washington Post.
As of 11pm this evening Buoy 46071 south of Amchitka Island in the Western Aleutians has recorded seas to 41 feet🌊🌊!! Here is a picture of the massive waves caught on the buoy’s camera. Adak Island has recorded multiple gusts to 75 mph and reached 70°F. #firstname.lastname@example.org/oDQhjzVZ5W
Coastal flood warnings and high wind warnings both remain in effect until late Saturday evening, while storm warnings have been hoisted at sea to warn mariners of extremely dangerous conditions.
Gusts could top out around 90 mph in some spots, with hurricane-force gusts up to 80 mph expected around Nome.
Water levels in the coastal town of 4,000 are likely to top out at 8 to 11 feet above high tide. In nearby Golovin, water levels will be even higher, pushing 9 to 13 feet above their normal high tide level, according to the Weather Service.
The strongest storm in over a decade is moving into the Bering Sea. Impacts may exceed the 2011 Bering Sea Superstorm, and some locations may experience their worst coastal flooding in nearly 50 years. Peak water levels will persist for 10 to 14 hours before water recedes. #akwxpic.twitter.com/l1Ik4iXYBG
In Nome and other villages along the northern Bering Sea, Plumb worries that water pushed into communities by powerful southwesterly winds will inundate structures, wash out key roads and damage important infrastructure.
Strong gusts of up to 90 mph could also easily take down power lines and cause other damage.
The massive storm surge and gigantic waves that may crest at over 50 feet would cause heavy beach erosion at any time of year, but the fact that the storm is striking in September heightens the erosion risk.
In addition to the storm surge, this storm will also bring very strong winds to the West Coast. Winds may gust up to 90 mph in areas such as Savoonga, Diomede, and the Bering Strait. Other areas can expect gusts in the 70s, with gusts as high as 80 mph possible. #akwxpic.twitter.com/gG95I6XyOb
When massive, extratropical storms track through the Bering Sea, it is usually later in the year — particularly into November and December. By that time, sea ice has built up along the coast, buffering significant wave action. But with this major storm striking in September, the coastline is without its icy barrier, making it particularly vulnerable.
“This will be the deepest low we’ve ever seen in the northern Bering Sea in September,” Plumb said, adding that this would be a strong storm at any time of year. “It’s taking the classic textbook perfect track for causing significant storm surge in the northern Bering Sea.”
A September strike is also concerning because it is still hunting season in September, meaning hundreds of people may be hunting in the remote Alaskan wilderness and not getting updates about the storm.
The road that many hunters and Alaskans use to travel inland, the Nome-Council Road, might end up washed away by the storm, leaving off-the-grid hunters stranded in the wilderness.
The system is similar to a disastrous storm from November 2011, when a comparably intense nontropical low pivoted through far eastern Russia, just inland of the Bering Strait. That month, too, the Pacific was forced inland; in Nome, roads and a sewer plant were swamped, while a number of low-lying coastal communities saw significant erosion wrought by the pounding waves.
“In the Nome area, or that part of the southern Seward Peninsula, everything is on track and it looks like [this storm] will be as bad or worse than the 2011 superstorm,” Plumb said.
In the Fourth National Climate Assessment, a comprehensive climate change report looking at impacts in the United States published in 2018 — scientists expressed concern that climate change has set the stage for greater impacts from large nontropical cyclones in Alaska. Warmer summers and oceans have caused a greater-than-normal seasonal loss of sea ice, which makes the region more vulnerable to ocean inundation.
“For coastal areas, the damage from late-fall or winter storms is likely to be compounded by a lack of sea ice cover, high tides, and rising sea levels, which can increase structural damage to tank farms, homes, and buildings and can threaten loss of life from flooding,” the report reads.
The report adds that coastal erosion rates have been hastening, with some spots on the coastline losing up to 100 feet of land to the sea each year.
“Longer sea ice-free seasons, higher ground temperatures, and relative sea level rise are expected to worsen flooding and accelerate erosion in many regions, leading to the loss of terrestrial habitat and cultural resources, and requiring entire communities, such as Kivalina in northwestern Alaska, to relocate to safer terrain.”
A meteorologically perfect storm
The powerful weather system blasting Alaska is, atmospherically, something of a perfect storm. The remnants of Merbok, once a Category 1-intensity Pacific typhoon, merged with a pair of nontropical storms as it veers toward the Bering Strait, the thin strip of water between Russia and Alaska.
Typhoons — the Western Pacific equivalent to hurricanes — run on energy from the hot oceanic water common near the equator in late summer. This contrasts with extratropical cyclones, which run on the energy held in atmospheric temperature gradients.
When the two types of systems merge, the combination can result in an immensely powerful storm that forms in a short time. This system explosively strengthened as it entered the Bering Sea.
Such a process strengthened Sandy considerably as it approached the Mid-Atlantic in 2012, and it will dramatically intensify the Pacific storm as it lurches toward Alaska.
On Friday, the atmospheric pressure in the center of the storm bottomed out at around 937 millibars over the Bering Sea, the lowest in the region during September since 2005. Low pressure draws air rapidly inward, like a vacuum, and values below 950 millibars are typically seen only in Category 3 or Category 4 hurricanes.
But because the storm, at this point, is something of a hybrid between a tropical and nontropical low, the wind field will not mimic that of a Category 4 hurricane. Instead, all of that energy will be spread out over a larger area, with a lower maximum sustained wind speed — likely around 90 mph — but with a far greater reach.