Forecasters are warning of high winds and possible flooding from the remnants of a typhoon on track to hit western Alaska on Saturday.
Ex-Typhoon Halong passed by Japan earlier this week and is on its way into the Aleutians and the Bering Sea.
The storm is bringing with it wind that could reach as high as 80 mph in some places and the potential for flooding and coastal erosion. That's according to the National Weather Service, which has issued weather warnings or watches along most of Alaska's west and northwest coast, from the Kuskokwim Delta all the way north to Utqiagvik.
Rick Thoman, a climatologist with the Alaska Center for Climate Assessment and Preparedness, is watching ex-Typhoon Halong closely. He says there's some uncertainty about exactly where the storm will hit Alaska and some big questions about its impacts.
This interview has been lightly edited for length and clarity.
Rick Thoman: It looks like the impacts will start to be felt on the on Alaska lands first in the Pribilofs, and then Saturday, later in the day, Saturday evening, looking for the (Yukon-Kuskokwim) Delta, especially, but probably not exclusively, north of Nunivak Island, as very strong south winds blow across that area. Places that have a southern exposure, places like Hooper Bay, are really in the sights for the first large-scale impacts of this.
After that, the storm continues to move north, crosses St. Lawrence Island during the day Sunday, and at that point, very strong winds into the southern Seward Peninsula coast, push of high water into the coast, into Norton Sound. That's going to be really the worst time for those areas in the Bering Strait region.
Casey Grove: And what can people expect? Especially in, like you mentioned, Hooper Bay and the Yukon-Kuskokwim Delta, getting hit starting on Saturday, it sounds like. What kind of wind and precipitation do you expect?
RT: Well, that is going to be something that's maybe somewhat different than some coastal flood-producing storms that we've had. Of course, they all bring lots of wind, but because this storm looks to be particularly intense, there is going to be, in all probability, much stronger winds on land than some storms that are producing coastal flooding, by having this very long fetch of strong winds across the ocean. Here we're going to see very strong winds on land, even in coastal communities. It's entirely possible that we will see gusts to 60, to 70 miles an hour, sustained winds, 40, maybe 50 miles an hour in places that don't typically get winds quite that strong.
CG: And then even farther to the north up the coast, you mentioned Norton Sound, which of course got hit by a storm early this week. Kotzebue saw pretty widespread flooding. Is the concern for that region more about more flooding there?
RT: Absolutely there's the threat of more flooding. It certainly looks like for the Norton Sound communities that water levels will be higher in this storm than they were earlier this week, particularly the areas from Nome eastward look to really have potential for very, very high water levels, significant coastal flooding.
I do want to stress, though, it's a very difficult forecast situation, in that slight shifts in the storm track will make potentially a big difference in just how much water gets shoved into the coast at any given place. So, you know, often it wouldn't make a lot of difference to the forecast, but here, if the low, say, winds up passing over western St. Lawrence Island versus Eastern St. Lawrence Island, that is going to mean very different outcomes for some communities on the on the Norton Sound coast.
CG: Gotcha. I had seen in the National Weather Service forecast discussion some comparisons to ex-Typhoon Merbok from a few years ago, I guess 2022, and people remember that. How would you compare, I mean, based on what you know about this now, this ex-Typhoon Halong, how would you compare the two?
RT: So there are some similarities between the two. Merbok in 2022 developed way east of Japan over near-record warm waters over the subtropical Pacific and then moved north. We have actually even warmer waters in the North Pacific this time than we did in 2022, and that's probably helping to fuel ex-Halong. It will be taking a path farther east as it crosses the Aleutians than Merbok did. There's that climate connection to the intensity of this storm.
One important difference, though, between this storm and Merbok in 2022, this storm looks to be moving fairly quickly, more quickly than Merbok did, even though it may be more intense, so lower pressure as it moves into the northern Bering Sea. So that forward speed means that there's less time for that water to be pushed up. A slow-moving storm in the Bering Sea has more time to push that water ahead. Here, the plow is coming by quickly, and so that may help to tamp down the water levels just a little bit. But places like Hooper Bay, which in that very constrained bay, open to the south, or Norton Sound, where there's plenty of room to pile up water, those areas are still in very, very high risk.
CG: Yeah. Now, you're a climatologist, and you mentioned that warm water and how that contributes to the intensity of these storms. And just thinking even longer term, is this something that we should be expecting every fall, early winter, that these intense storms are going to be even more intense, and we're going to see more of these?
RT: We certainly have seen ex-typhoons before Merbok. But as the oceans warm, that's providing more energy to the atmosphere in the form of more water vapor. And so we're not going to see these every fall — it's been three years since Merbok — but the chances of all the pieces coming together, we need lots of individual pieces to come together in the atmosphere and in the ocean, and when they do, just by having warmer oceans, we up the chances of these really extreme storms.
CG: So there was the storm that flooded Kotzebue this week. There's this ex-Typhoon Halong hitting this weekend. And then, did I see in the forecast that there's another big storm heading towards Alaska next week?
RT: I guess we have the almost obligatory, "But wait, there's more." It does look like there's going to be another storm in the Bering Sea here early next week. It looks to take a different track, and places that are not going to be severely impacted by this upcoming ex-Halong, places like Bristol Bay, are looking to be more under the gun for early next week. A storm with strong winds and lots of rain and probably the seas will get cranked up in Bristol Bay.
CG: The hits just keep coming, as they say.
RT: The hits just keep coming. It is that time of year, and it's that kind of fall.