A weak but strengthening disturbance has been doing a slow loop just south of eastern islands of Indonesia and East Timor. It has dumped epic amounts of rain over the region, causing tremendous flooding. Thirty thousand have been evacuated, and while 97 deaths have been reported as of this morning that number will undoubtedly be higher as several flash floods hit at night. In the words of one official:
Most of this damage happened before the cyclone became organized enough to become a named storm. Now known as Seroja, the cyclone (in the Southern Hemisphere hurricanes are called cyclones) the system is moving away from the islands and headed towards the west coast of Australia, where it may be nearly category 3 (major hurricane) in strength when it makes landfall.
Like a bad remake of Groundhog Day, it’s that time of year when the various research groups emerge from their ivy covered lairs and issue forecasts for the upcoming Atlantic Hurricane season. I used to play that game, with the annual press conferences, media interviews, and associated tabulation of number of articles and citations to go into the next annual report and round of funding requests. But the last decade or so I have given up on the annual media circus as NOAA has started issuing its own estimates, and our research has moved on to site specific seasonal impact estimates rather than simply counting the number of storms. After all, having 20 storms doesn’t matter if none of them hit you; likewise, one storm can ruin your decade. So while this post does end with a suitably depressing outlook for 2021, it is more about the influence of the big driver of storm activity in the Atlantic: the ENSO or El Niño cycle.
The El Niño-Southern Oscillation (ENSO) has a huge impact on global weather. Although the usual way of measuring it is in terms of East Pacific sea surface temperatures, ENSO is a complex phenomena that changes both oceanic and atmospheric circulation patterns worldwide. The Wikipedia page has a nice overview of the system; what concerns us here is the impact on hurricanes. In the Atlantic, the warm phase of ENSO (El Niño) typically depresses hurricane activity; likewise, the cold phase (La Niña) tends to result in more and stronger storms. Periods in between are called “ENSO Neutral” or neutral. The reason ocean temperatures in the Pacific influences Atlantic hurricanes (in another ocean thousands of miles away) are complex, but mostly have to do with wind shear over the Atlantic and the so-called “steering currents” that push storms around as they move across the ocean. Don’t confuse these Pacific SST’s with ocean temperatures in the Atlantic – that is a separate cycle and phenomena. Normally we associate warmer oceans with more hurricanes, but in this case, a warmer Pacific during a El Niño phase means the Atlantic becomes less favorable (at least from a wind shear perspective)! The worst combination is a cold Pacific (La Niña) and a warm Atlantic: the cold Pacific is cold because winds are favorable over the Atlantic, and the warm Atlantic means more energy for Atlantic storms. Confused yet? Don’t be – in this case it’s simple, we’re just looking at how the three phases of ENSO correlate with hurricane landfalls and damage since it is such a big factor.
Let’s take a look at the peak of hurricane season, the month of September to see what impact the contrasting ENSO phases have on the number of storms, as well as on damage. Using data since 1871, it’s pretty even split between the two contrasting conditions. About 25% of Septembers are El Niño, 24% are La Niña, whereas 51% are neutral. But in terms of total numbers of storms, 30% occur in La Niña years, whereas 22% occur in El Niño. That doesn’t seem like much on the surface, but it actually translates in to a significant difference in the number of storms between the two years – an El Niño September typically has one third fewer storms than either a neutral or La Niña year. The number of people impacted by hurricane conditions also reflects this difference in a similar way. About a third fewer people are impacted by hurricane conditions in an average El Niño September than in other kinds of years. Damage basin-wide is not quite so dramatic, with damage during La Niña years only about 25% higher than in El Niño. But … there are regional twists to this story.
The biggest driver of the economic impact of hurricanes in the Atlantic is of course the mainland United States. The US experiences nearly DOUBLE the economic impact of hurricanes in an average La Niña September as compared to El Niño years (33% vs 17%)! This is partly due to the higher intensity, but more importantly due to the landfalls in La Niña years being closer to high value exposures (cities, or targets if you prefer 😮 ) in the Northeast and Atlantic coasts. Looking at the other two active months, La Niña Augusts tend to have more storms – but those storms stay offshore, so the damage actually tends to be less than in El Niño years, but in October the impacts are dramatic. A La Niña October tends to generate three times the damage as an El Niño year.
If you look at individual states there are also dramatic differences. In Florida, La Niña Septembers have generated FOUR TIMES as much damage as El Niño years! In New York, New Jersey, and Massachusetts there have been so few El Niño losses the computer said “Fuhgettaboutit” when I asked, they are so rarely damaged during those years, and La Niña years are so bad. The Gulf Coast isn’t quite so dramatic, but still Louisiana has had just under twice as much damage during La Niña.
Another interesting area is the Georgia/South Carolina Lowcountry coast (south of Edisto Isl). The unusual shape of the coastline, combined with being at the latitude where storms begin to recurve to the northeast means that for hurricane damage, the difference between La Niña and El Niño isn’t quite so dramatic – only about a 30% difference. However, unusually, activity is depressed in ENSO Neutral years, and elevated in both La Niña and El Niño Septembers.
What can we expect for this year? The current ENSO forecast for August to October is that we will almost certainly be at least neutral, and there is around a 50% chance of being back into La Niña conditions by September, and a higher chance for that in October. While not as favorable as last year, that’s Not Good for hurricane season, as it means higher than average activity. Therefore, I expect the hurricane forecasts coming out over the next few weeks to reflect that. Not likely as many storms as last year, but very likely to have multiple threats over the season. But there are a lot of other factors that go in to how many storm form in a given year, much less where any individual storms goes once it forms. The atmosphere is a very complex beastie.
So let the scare mongering begin … or, you could just enjoy the beautiful spring weather, the flowers blooming, and consider that as bad as hurricanes are, and unlike tornadoes that give you little warning, or earthquakes that give you almost none at all, you can see them coming days away, and have time to get out of the way. So as a reminder, this is the time of year to revisit your hurricane plans, especially insurance. There is a “lock out” period for changes prior to a storm and if you wait until one is headed your way, it’s too late. Check out Ready.gov for checklists and advice.
Busy global map this morning … lots of earthquakes, four tropical systems …
Zooming in to just off shore from New Zealand, with hundreds of earthquakes along the Kermadec Trench boundary between the Pacific and Australia plates, just off the coast of New Zealand. Three of these were over magnitude seven, one being a magnitude eight that triggered tsunami watches as far away as Hawai’i … each icon represents an event that caused shaking at the surface (sea floor mostly in this case), most of these are M5 or greater events, the red aeras are areas where if you were standing you would have felt it:
Models estimate total economic impacts at just under $1 Billion USD. Before anyone asks, the earthquakes and cyclone are unrelated – although tropical cyclones have been associated with earthquakes due to the pressure of the storm surge causing a rupture, or in some cases infiltration of extensive rains perhaps triggering the earthquake. This is an area of ongoing research.
The other cyclones are well offshore, Cyclone Habana in the mid South Indian Ocean is a powerful Category Four (120kt) storm. The Southern Hemisphere season has been pretty active this year with several very strong storms. Naturally some are saying it is climate change related – and that’s very possible. Unfortunately our historical data sets for that region are spotty at best, so the arguments have to be largely theoretical. I hope to do a post on this at some point soon.
On the COVID front, the numbers continue to go up in some places, down in others, causing mood and behavior swings that means the pandemic continues to oscillate and travel in “waves.” Additional vaccines are being approved and distributed, based as much on politics and economics as efficacy and logistics. I find the “news” coverage in the US depressing on this topic (and, again, the real time death counters that CNN is running are misleading, BOGUS fear mongering – it takes weeks to get solid data on mortality). In any event, in big picture terms little has changed in terms of what the average person should do: continue with masking in public (despite what Texas and Mississippi are doing), distance as appropriate, if you are eligible and it makes sense for you specifically from a medical perspective get the vaccine, get it (in other words, balance the consequences of COVID, which are severe, with the unknowns and any specific vulnerabilities you might have, and your personal situation regarding risk – both higher and lower).
I had a great question come in from a reader about the difference between emergency use authorization (EUA) and the standard review and approval process. There is a big difference between “Authorization” and “Approval” in the Food and Drug Administration (FDA) world. Here is a discussion with a former FDA official on the Johns Hopkins School of Public Health site. The short version is it is the difference between “might work and shouldn’t hurt” and “has been shown to work with acceptable side effects.” For the vaccines, the main differences are that the threshold for effectiveness is not the same as for an approved vaccine, and most importantly the long term side effect studies and studies on potential interactions and co-morbidity (reactions, impact on fetal or child development, and so forth) are not as extensive and have not had time to collect data. As I noted previously, there is a big difference between making a theoretical argument on those topics and saying “there is no evidence” based on a few months of results, and saying “we tried it, watched for five years, and there were no observed effects.” Given the medical and socioeconomic impacts of COVID, the FDA has made the calculation that the risk of being wrong about adverse reactions and efficacy is outweighed by the benefit of quickly getting a handle on the pandemic. I think they are mostly right about that (with a few reservations I’ve expressed previously). Again, for a lot of people, getting vaccinated makes sense. But everyone should understand the process and risks, free from either blind cheer-leading or paranoid fear mongering.
We have three cyclones in the South Pacific, with two of them criss-crossing Fiji and one off of Australia headed towards New Caledonia …
Cyclone Ana is just past the main islands of Fiji, having passed over the capital and causing a lot of flooding. Right behind it is Cyclone 16, which may not reach hurricane status but will cause even further damage and misery. To the west is Cyclone Seventeen, which is headed towards the French territories of New Caledonia. It may reach major cyclone status before turning south towards the islands, is forecast to be a weakening tropical storm as it passes over the Loyalty Islands (the group of islands just to the right (east) of the “New Caledonia” label on this map).
Watching the developing Nor’easter on the US East Coast. It is windy here in Savannah this morning and rain should be moving by this afternoon, erasing the pretty blue skies. Be careful on bridges in the area this afternoon – the National Weather Service issued a special weather statement for the coastal GA/SC area, with winds expected to pick up to 35-40mph. Will try to do a post around lunchtime with the details …
It’s been super busy and I’ve been swamped trying to reset things after major changes my organizational landscape, but we continue to have the usual share of doom stalking the Earth: it’s hurricane season in the southern hemisphere, there have been a couple of significant earthquakes. The SARS-COV-2 virus that causes COVID-19 continues to be doing fine (humans not so much), and of course there is something happening in Washington DC today …
There are three active tropical cyclones in the Southern Hemisphere, two “invest” areas, and another invest area in the Philippines(!). Most of these are fairly weak systems, but Cyclone Eloise has just made landfall in Madagascar and is headed towards the African Mainland. The forecast models, as well as the official forecasts from MetoFrance (who are responsible for this area) and the US Joint Typhoon Warning Center, show it strengthening into a hurricane before the second landfall. Here’s the impact estimate …
There has been a rash of earthquakes causing moderate damage over the last week. The two most significant are a series of quakes in San Juan province of Argentina, and a major earthquake causing significant damage near Sulawesi, Indonesia. Nearly 100 are known dead, while humanitarian situation among survivors in Indonesia is becoming of concern. Damage in Argentina seems mostly confined to infrastructure.
COVID continues a slow burn through the population. It has been over a year since the first warnings were raised, and I have a longish post under construction looking back on the early predictions, as well as where we seem to be going from here. Hopefully will get posted in the next day or so, reviewing some of the latest data. It’s not good, and while it’s not the black death, it is still killing a lot of people who would not otherwise have died, and anyone who says otherwise is wrong. Period. That said, there are some interesting trends in mortality from other causes (such as influenza, which is almost non existent this year).
Due to the inauguration, the normal weekly data update won’t be out until tomorrow, which will give us our first mostly complete look at the 2020 mortality data, so the post will likely be on Friday. To rant once again, there is NO REAL TIME DATA ON COVID19! The “death counters” on TV are bogus. Johns Hopkins (the source most are using) is doing a great job, but the daily totals, especially of mortality, are very noisy estimates. This is a slow moving disaster; it takes a couple of seeks for all of the mortality data to be compiled.
It still astonishes me that people can’t seem to get grip on this thing, and how politicized it has become. Of course, it shouldn’t; sadly the reaction of people and what policies they want to enact are pretty predictable based on party. And like most things a balanced approach would do far better than either extreme. We’ll see how the “new” Administration does. Speaking of which …
The Biden Administration takes over today. A lot of things will likely become more orderly, and while their domestic polices are not accepted by almost half of the population, the rollout and implementation will be well organized given the long government pedigrees of the President and his various appointees. And given the fact the US media is largely on their side, stuff will get done and things will certainly appear to be better. But I’m extremely concerned about Foreign Policy. This group, lead by Blinken, Rice, Powers, and the new torturer in chief, Avril Haines, are responsible for inflaming many of the world’s trouble spots such as in the Middle East (especially Syria and Libya). They are largely responsible for the confrontation with Russia over Ukraine, and advocate policies that are likely to create further dangerous conflicts. Unfortunately, much of that will be “under the radar” as the US public and media focus on the domestic situation.
Administrative note: I’m no longer cross posting any politically focused posts on either Facebook or Twitter. The environment just isn’t conducive for rational discussion, and I don’t want the Enki FB page to become yet another site where people I don’t know engage in poo throwing contests 😛 … I’m happy to discuss the political implications of various doom we face (and most of them do involve politics), but we need to keep the anger and emotion to a minimum, and try to keep things based on all the facts (not just the ones that support some particular point of view). All that said, the new year is starting off much better (organizationally, if not funding wise) than the last, and the reorganization should finally start to be seen in better stuff on the Patreon page and web sites any day now 🙂
While the snowstorm made headlines in the US yesterday, cyclone Yasa crossed the islands of Fiji yesterday …
Loss of life seems light, two deaths confirmed so far as of Friday morning US East Coast time, but damage is extensive. Fortunately the damage swath missed the more densely populated island of Viti Levu and main city of Sava, but it is still likely that Yasa caused upwards of $100 Million USD in damage. That may not seem like much, however for some perspective that’s around 1.8% of GDP, so it would be the equivalent of 360 Billion dollar storm hitting the US, or over three Katrina/Sandy class storms.
The 2020 Atlantic Hurricane Season has ended, and there have been much written about the record setting number of named storms. There are several issues with the numbers based on named hurricanes. The problem is that these are based on shifting criteria (naming) and technology (wind speed measurements) that tend, in my opinion, to make recent seasons (especially since 2000) look worse than they really are in context. While it was a very active season with significant damage and impact, the total number of storms is a bit exaggerated – several storms would probably not have been named using the criteria prior to the mid 2000’s. Here are a couple of other ways of looking at things to put the season in perspective.
One measure of the intensity of a season is the Accumulated Cyclone Energy (ACE) index. It is summing the square of the wind speed for each storm at six hour intervals (recalling that the kinetic energy is related to the square of the wind speed). By that measure the 2020 season is the 13th most active since the mid 1800’s – with the caveat we know there is an undercount of storms, and likely an underestimation of intensity (by modern standards) as well, especially for storms that did not make landfall. So more than likely 2020 was still in the top 20, but probably not above 15th.
What about damage? By that measure, if we use the existing distribution of population and infrastructure for past storms, again we have a bad season (especially for the Gulf Coast and Central America), but depending on how you crunch the numbers far from record setting. 2020 just breaks the top 10 in total damage.
It does better if you use the criteria of the number of people who experienced tropical storm force winds, coming in at number two, but that is a bit misleading because many people are counted twice (or even three times) since Central America and Louisiana were hit by more than one intense storm. Taking the double counts out it drops to eighth (2012 is by far number one due to the broad Sandy wind field sweeping through the densely populated northeast).
So the official Atlantic season ended on November 30th. There is still an invest area in the far eastern Atlantic that has winds well above tropical storm strength, but it does not really have tropical characteristics so has not been named. There is a cyclone at tropical storm strength about to make landfall on Ceylon today, followed by southern India. And the southern hemisphere season is kicking off … the world keeps turning and the seasons change, but there are always weather disasters going on somewhere. For the Blog, will continue to report on cyclones and earthquakes of course, but will be posting more on winter storms in the coming weeks. Interestingly, for many years the biggest property insurance loss numbers come from broken pipes … and you haven’t really experienced terror until you’ve driven the perimeter in Atlanta (much less navigated Spaghetti Junction) with so much as a single ice crystal sighted in Marietta 😛
In the Atlantic, the US National Hurricane Center has two “watch” areas, one of which is being tracked as invest area AL99. Neither are a threat to land at the moment, and arguably don’t have much potential to become actual tropical systems, although AL99 might develop some hybrid characteristics and meet the forecast criteria for a “subtropical” system by Sunday.
Although it is still raining in places, the flooding is receding in some areas of Honduras and Nicaragua, and the process of assessing the damage is underway. This is a huge natural disaster (EuroNews summary in this link) that does not seem to be getting as much attention as it probably deserves. Some are saying it will ultimately prove worse than 1998’s Hurricane Mitch. The death toll so far is much less, but the economic impact seem to be on par with Mitch. And there will possible yet a third disaster: conditions for the estimated 250,000 people who sought shelter are conducive to spreading the virus that causes COVID19, so disaster planners are concerned that there will be an explosion of cases in the region in the coming weeks.
Elsewhere, NHC has a broad region south and east of Bermuda flagged as a 10% chance of subtropical storm formation in the next 5 days. The NCEP objective probability model has it below 3%, but still shows some potential for formation in the southwest Caribbean in the region still generating rain over Central America. There are two “invest” areas in the Indian Ocean forecasters at JTWC are watching, one that might become a tropical depression before hitting Somalia …
The US National Hurricane Center has two watch areas but neither are much of a threat of becoming an actual tropical system at the moment, both tagged as less than 20% over the n next five days. That said, one of them is associated with a low developing in about the same place that Iota formed. That system is likely to drift over Central America dumping even more rain on the ravaged region. Here’s this morning’s analysis from TAFB, overlain on the mid level water vapor image from GOES East. Compare how moist the air is streaming into Central America (grays/whites with colored blobs of storms) with the cool dry are to the north (oranges/reds) ..
In the East Pacific, Tropical Storm Polo is off the coast of Mexico, and will fade out over water. Nothing in the West Pacific, in the Indian Ocean the Joint Typhoon Warning Center is watching a system in the Arabian Sea that is in a somewhat favorable environment but not likely to develop in the next day or so.