Quite the day out in weather world, although you wouldn’t know it from looking outside here in the land of the corn. Beautiful day, although still waiting for the leaves to make an appearance. Soon enough, but the sun shines bright overhead. Calming and peaceful for a walk later.
After a winter which was tumultuous with big temperature swings (sometimes 50 degrees F within days), it’s nice to have a little stability for some days. Looking near or mildly above normal temperatures the next several days with periods of rain showers. Our winter in this region was less than 0.5 C below normal relative to 1981-2010, but running 0.5-1 C above normal relative to 1881-1910 when factoring the effect of climate change. And temperatures from anthropogenic climate change began rising globally after the mid-1700s, so late-19th century values are still conservative on the changes which have occurred here. People around here were complaining about how cold it was this winter. It could’ve been a lot worse as we had a few 60 and 70 degree temperatures in February mixed with the 10s and 20s for highs in January and February! Just wild.
Actually reminds me of a story in the coffee shop of a mother and adult daughter discussing this past winter. The daughter saying how “normal” it was to have these huge swings in temperature and crazy weather (snow then short-sleeve weather). Mother saying “Well I remember when I was young, it would be more consistently cold with a lot more snow, not like now”. What’s normal has changed with time in a lot of world, but you wouldn’t know it unless the different generations notice and chit chat about it.
Our chances of snow appear to be over. Never say never, as the East Coast seems to be getting blasted by these cold storms, but when you start seeing these consistent mild conditions finally, it’s usually a sign of the seasonal transition…finally.
I do have some concern over this Spring’s tornado season I must say. La Nina periods in the El Nino Southern Oscillation tend to be known for quite intense tornado outbreaks. Trying to get a science paper reading in about it this week if I can. The Gulf of Mexico waters are running above normal for moisture, the South has been quite warm overall with record warm days and months this winter. And jet stream dynamics continue to be favorable for bringing periodic shear profiles for significant severe weather. The atmosphere put on quite a show this weekend in the Deep South where it is climatologically favorable for tornado activity. Reminds me to prep an emergency kit. We do have a weather radio, but with things like tornadoes and urban flooding, you never know when you will need a little more to get through a few days of darkness and no refrigeration.
While, it’s quiet here, the West and East Coasts are being battered by major winter storms to start Spring. Very strong upper-level trough over the eastern third of the country and another over the Eastern Pacific means the 4th nor’easter of the month in the East and huge atmospheric river event in Southern California. Heavy snow or flooding/mudslides?
Good mid-week to all and stay safe in these stormy areas!
Cyclone Gita in the South Pacific is a powerful Category 4-equivalent tropical cyclone on the Saffir-Simpson Scale (as of the time of this post). Maximum sustained winds analyzed by the US Joint Typhoon Warning Center are up to 130 mph with gusts to 155 mph. Gita is moving westward and is expected to pass near or over Tonga around 12 UTC Monday (6 am CST or 1 am Tuesday local time). The storm is expected to be at least a powerful Category 4 storm. There is moderate wind shear (increasing winds with height effecting the cyclone and limiting more rapid intensification. However, with water temperatures along the path of 28-29 degrees C (82-84 degrees F) and well-organized structure, Gita will be a potentially catastrophic storm if its eye wall moves over the main island. Gita will also produce very heavy rain (perhaps 6-12 inches) which will lead to flooding. A state of emergency has been declared in the island nation.
After 24 hours, Gita is expected to gradually weaken as sea surface temperatures cool and vertical wind shear increases as the system begins to turn to the southwest into higher latitudes. However, Gita is expected to remain a hurricane-force storm through the end of the week.
New Zealand will need to keep an eye on the remnants of Gita as the dying circulation an moisture plume may curve back southeastward in the mid-latitude westerlies. While, the forecast will certainly change somewhat…such as the position of the upper-level trough of low pressure southwest of New Zealand which will cause the system to curve back towards the country beginning Sunday…any remnant system may lead to locally heavy rainfall for both the North and South Islands early to mid-week next week.
The 2017 North Atlantic Hurricane season was a devastating one in terms of loss of life as well as property damage for the United States and the Caribbean. The National Hurricane Center released its post-season report on Harvey which caused great destruction to parts of Southeast Texas and Southwest Louisiana. What follows is a brief summary and discussion of Harvey based on info from that report as well as other sources related to Harvey’s impacts. The full report is linked at the end of this post in the references.
What became Harvey was originally a tropical disturbance which came off the West Coast of Africa on August 12th. It is common during August and September for land-based thunderstorm complexes known as mesoscale convective systems to move westward off the African coast near or south of the Cape Verde (also known as the Cabo Verde) Islands and later develop into long-lived tropical cyclones. Harvey was a classic “cape-verde” type storm as it would later develop into a tropical depression with a well-defined center on August 16th.
The depression intensified into a storm and given its name 12 hrs after initial development. It peaked over the open Atlantic at 40 knots (~45 mph), moving over the islands of Barbados and St. Vincent on August 18th. However, increasing vertical wind shear (increasing winds with height tilting and blowing the thunderstorms away from the low pressure center) over the central Caribbean Sea lead to Harvey’s dissipation to a remnant low later that day.
The remnant circulation moved over the Yucatan Peninsula on Aug 22nd and redeveloped into a tropical depression over Bay of Campeche on August 23rd, 150 n mi west of Progreso, Yucatan, Mexico.
The initially poor organization of the reformed Harvey transitioned to a period of rapid intensification late on the 23rd as deep convection began to concentrate near the center. This was aided by an environment of light shear, very warm sea surface temperatures and high mid-level moisture. Intensification would continue until landfall on the 26th. Harvey reached Category 3 midday on the 25th and intensified into a Category 4 as it made its landfalls on the Texas coast early August 26th (the evening of the 25th local time). The initial landfall was on San Jose Island, TX as a Category 4 with maximum sustained winds of 130 mph (115 knots) with a second landfall on mainland Texas in northeast Copano Bay as a Category 3 with maximum sustained winds of 120 mph (105 knots). Wind damage was extreme and devastating in Aransas, Nueces, Refugio and the eastern part of San Patricio Counties. 15,000 homes were destroyed and 25,000 homes damaged. The City of Rockport was hit the hardest as the Category 3+ wind field moved into that area causing both extensive wind and surge impacts. The highest surge observed in Harvey was generally in the range of 9-11 ft.
Harvey meandered in light steering currents, “stuck” between a mid-tropospheric high pressure system over the Four Corners states and another mid-troposphere high over the Gulf of Mexico. Torrential rains fell over Houston Metro and the Golden Triangle near a stationary front which formed on the north and east side of Harvey.
The rainfall of Harvey was truly incredible. A storm total of 60.58 inches was confirmed Nederland, TX; 60.54 inches in Groves, TX. Much of the heaviest precipitation fell in the first 72 hrs of the event. Previous continental US record for a tropical cyclone is 48 inches in Medina, TX (1978). The extreme nature of Harvey was displayed in that 18 values over that continental record of 48 inches reported across southeastern TX, with 36-48 inches recorded across the Houston metro area. However, Multi-Sensor Precipitation Estimates (MPE), which includes radar-derived rainfall intensity estimates suggests 65-70 inches where few observations were available or observations failed early in the event. Maximum rainfall measured in Louisiana was 23.71 inches in Vinton, LA, with MPE suggesting a more representative 40 inches as Southeast Southwest LA obs were sparse.
The large-scale or synoptic set up for the Harvey exceptional rainfall event is not particularly unique. Heavy rain bands formed along a modest frontal boundary situated initially near Houston, then the Golden Triangle region in Southeast TX (Beaumont, Port Arthur, Orange, TX area). Enhanced convergence and convective lift with warm cloud droplet precipitation processes allowed for enhanced rainfall rates in abundant thunderstorms. The combination of extremely high rainfall rates of up to 5-7 inches per hour and the stationary nature of the near coastal frontal boundary and Harvey itself contributed to the extreme total accumulation and massive flooding.
NOAA analysis determined that areas of Southeast TX experience a flood with an annual probability of <0.1% (equivalent to a >1000 year flood event). I believe this is one of the most important parts of the National Hurricane Center report, so I’ll quote it:
While established records of this nature are not kept, given the exceptional exceedance probabilities, it is unlikely the United States has ever seen such a sizable area of excessive tropical cyclone rainfall totals as it did from Harvey.
In addition to storm surge, wind and flooding rains, Harvey produced 57 tornadoes (many in the Houston Metro area) and killed 68 people directly with an additional 35 indirect deaths. All direct deaths were in Texas and it was the deadliest tropical cyclone for Texas since 1919. All but three direct deaths were caused by freshwater flooding.
According to NOAA, preliminary damage analysis suggests estimated damages of $125 billion, making Harvey the second-costliest hurricane on record in the North Atlantic basin, only behind Hurricane Katrina, when adjusted for inflation.
Connection to Anthropogenic (human-caused) Climate Change
During and immediately following the events of Hurricane Harvey, there was intense controversy over even discussing climate change as it related to the extreme events related to Hurricane Harvey. Even mentioning climate change in reference to an individual extreme weather event. A lot of opinions were thrown about, but the science of climate change has evolved dramatically in the past 10 years and climate researchers have a much better understanding of many of the connections between climate variables and the statistics of weather which make up the recent past and current climate. From this, attribution studies can be conducted to determine a likelihood of connection to the changing climate regime. A attribution study was done by World Weather Attribution (#2 below) and the probabilistic statistical analysis determined that the record rainfall from Harvey was approximately a) 3 times more likely and b) 15% more intense in terms of rainfall rate because of climate change. One location witnessed a return period for extreme rainfall of 9000 years with a high degree of statistical confidence. The impacts were consistent with what would be expected with 1 degree C+ of global warming since the late 19th century (the world has thought to have begun warming because of humanity since the mid 18th century). I did an extensive post previously during this most recent hurricane season on the climate change connection with includes references to numerous recent peer reviewed papers HERE.
The first full week of January featured a powerful winter storm – known as a nor’easter – intensify off the east coast of the United States causing snowfall from the North Florida to Maine into Atlantic Canada, along with widespread power outages from strong winds as well as storm surge flooding and battering waves.
The storm underwent rapid intensification known in meteorological slang as “bombogenesis”. An “atmospheric bomb” occurs when a developing cyclone’s low pressure center intensifies explosively…defined as at least 1 millibar or 1 hectopascal drop per hour on average during a 24 hr period. This system had a pressure drop of 54 millibars in 24 hrs (1004 to 950 millibars). This bombogenesis phase can occur in both frontal cyclones seen in the mid-latitudes such as with this week’s storm or with tropical cyclones. A famous example would be Hurricane Patricia in the Eastern Pacific in 2015 which experienced a minimum central pressure drop of 95 millibars during a 24 hr period (967 to 872 millibars).
Bombogenesis in mid-latitude cyclones occurs when there are favorable jet stream dynamics which allow for strong vertical motion, to force air up and away from a developing surface low. These include very strong upper-level winds and diverging flow. This allows for a high rate of decrease in surface pressure, intensifies the pressure gradients, reinforces the “conveyor belts” of warm, moist air flowing into the cyclone for clouds, releases latent heat and producing precipitation, which further strengthens the storm.
For frontal cyclones, the most intense atmospheric “bombs” occur when you have a merging or “phasing” of the northern and southern jet streams (basically the polar jet with much colder air to its north and the subtropical jet with far richer moisture sources to its south). This “phasing” of jet streams occurred with the most recent nor’easter.
“Bomb” cyclones are nothing new. Unfortunately for us who have to live and deal with their impacts, human-induced climate change has forced our world to retain a significant amount of heat energy. These major changes on climate in just the past 20-30 years have caused statistical changes in observed weather. And one of those changes is in rapid intensification of cyclones. With tropical cyclones, there is evidence that a warming ocean and lower atmosphere (with greater moisture/latent heat release) is playing a role in increasing the frequency of rapidly intensifying tropical cyclones (here’s a paper by Kishtawal et al. on the topic). With mid-latitude cyclones, there is ongoing debate on the issue. However, there ongoing research suggests that in addition to thermodynamic roles, the increasing “waviness” of the polar jet stream theorized to occur in a warming world may have impacts on mid-latitude weather and long-term climate patterns. High amplitude jet streams produce greater mixing of air masses at lower levels of the atmosphere between the polar regions and sub-tropics (a process known as temperature advection). The increase in jet stream amplitude acts as a feedback to further amplify Arctic warming rapidly relative to the mid-latitudes as much warmer air advects into the far north (jet slows slightly with less temperature gradient, but becomes much more amplified, enhancing warming further). While the effect of the mid-latitudes circulation patterns on the Arctic seems more well-established because of the rapid changes in the far north, climate scientists are in much higher disagreement on the effects of feedbacks back on the mid-latitudes. Dr. Jennifer Francis (Rutgers University; see short webinar on possible connection between Arctic warming and mid-latitude extreme weather), among other scientists continue to do research actively on jet stream dynamics in the mid-latitudes with regards to climate change. But such a combination of warming energy sources and amplified jet stream patterns could further the development “bomb” cyclones in the future as the world continues to warm, at least while there remains strong temperature gradients between air masses to fuel mid-latitude storms (mid-latitude cyclones may be weaker and/or found much farther north in a much warmer planet). And there has already been a statistically detectable shift northward in winter storm tracks in the Northern Hemisphere and an increase in the severity (intensity of cyclones and precipitation rates) and frequency of “atmospheric river” events in the Eastern Pacific toward North America since the 1950s (see Key Finding #4-5/Chapter 9 of US Climate Report).
What “bomb” means as far as hazardous impacts will depend on the specific storm, but when it comes to ocean storms, like what was witnessed this week, obviously, damaging winds, heavy surf, storm surge flooding and heavy precipitation which can cause dangerous disruptions are what are all possible. In this case, much of it was all snow and ice. In the warm season, it can be flooding rainfall. But human-induced forcing (retaining of heat in Earth’s system) is now known to play a role in the attribution of the intensification of these large-scale weather systems within the changing climate regime.
I may, perhaps, be providing a less popular view or one which isn’t the “flavor of the week”. But I’ve been hearing a lot of people recently in science discussing the communication of climate change. There has much criticism of how some have chosen to communicate. Examples: Statements considered “dire”; assuming moral or intellectual superiority if someone disagrees with the most sound parts of the science; being condescending, etc.
First off…I do agree with the idea that people need to treat people right and fair. Do not treat people like they are less than you or unnecessarily scare them into submission. We need to communicate what we know and how we understand it and listen to what people have to say.
But with that said…
The science of climate change (and it’s main mechanism…global warming) has been gaining scientific ground since the 1970s. The understanding of the greenhouse effect and carbon dioxide goes back to the mid-1800s. I was born in 1984. Climate scientist James Hansen went before Congress in 1988 to give the realities of what climate change means. The Intergovernmental Panel on Climate Change of the UN was formed in 1988. It’s 2017. The climate of Earth has warmed dramatically since then and as a result we are witnessing impacts on our world from more extreme meteorological and climatological events, extinction rates 1000 times higher because of humans with a possible mass extinction event underway in the biosphere and millions around the world and increasingly direct impacts on human health. Meanwhile too many deny what is happening because data isn’t enough. And in many cases, many of the people we are trying to convince are not only disinterested in learning, but have a sharp anti-intellectual bent based on politics or even religion. I have no problem with people being politically conservative or religious, but that is the reality of who most of the “deniers” are. So are we not supposed to call out people who are grossly thinking irrationally or being outright deniers (not skeptics, skeptics can be convinced) in order to protect their feelings and “hopefully” convince them we are correct? Climate scientists are routinely attacked by denier politicians and on social media and their reputations dragged through the mud. Hell, even threatened. Who speaks up for the integrity of the science and scientists while we all sit around trying to be nice and protect the feelings of people who are not interested in what we have to say, respectful or not?
I guess the reason I’m rather sharp about this is because I think Americans largely discuss this topic from a position of privilege. In America, climate change is still a joke for many or largely downplayed. “Look at all this snow, I guess they got 5 inches of global warming hahaha”. “I get climate change is an important issue, but do people really think it’s as important as [insert political issue here]”. And other various statements. I think there are two issues at work here.
In the US, we are dealing with the impacts of climate change, but we (generally) still have the resiliency to face what’s happening. In the developing world, this is not the case. There have already been significant increases in extreme events relative to the mid-20th century (droughts, fires, heavy precipitation leading to issues such as increased property destruction, even more importantly, crop failures putting more people at risk of undernourishment). And in some places, there’s sea level rise becoming a problem. In the developing world, this is not a game, or a joke or something to be denied. It’s in their face. Even if individual event/event types can’t be conclusively attributed to climate change, understanding climate change is a *systemic* process of our climate heat engine, adding more energy can cause more extremes across many categories. How much to developing nations realize these growing extremes? They’ve realized it enough to basically demand the industrialized nations who have caused a vast majority of the warming of Earth via 20th century emissions, to work to limit warming to as low as possible and pay for their mitigation measures. Unfortunately, they are largely ignored because their countries are small and not economically influential enough (Paris Agreement basically is business-as-usual lite), so the world is failing and they will suffer the worst impacts of global failure first.
Climate change is to outright deniers “something that’s always happening” or even to many of those who understand the basic science a more significant concern of the future. 2100 comes up a lot. Or perhaps “We have 10 years” which was since the late 1980s. How many times can we have 10 years to seriously discuss these problems? Climate change is happening now and changes *are* going to accelerate and be abrupt as we move forward. How can we discuss these issues if too many people think they know better than a PhD with 30 years of research experience? If the PhDer asserts in a blunt manner that they know better, we might think that’s intellectual superiority and unfair assumption as we all have different experiences beyond education. And technically that’s true…but if one is degrading someone because they are educated and they trust what they see over data, can we call it what it is? Anti-intellectualism and in some cases even moral superiority as it may be based on religion or politics is just as bad if not worse to our society than anything. This is clearly something anyone can be out of line on.
Us “intellectuals” seem to be having debates about how to best communicate climate change. We should talk about the worse case scenarios, should be have lots of hope and solutions, this and that. My view? Tell the truth! How can we do anything about climate change if people do not actually have an appreciation of what we are facing in terms of how it can directly harm human society and our biosphere? I’ve noted that even many outside of climate science do not fully appreciate what is happening now and how bad it could be. The “worse-case” is not…it is the path we are on in all of its unpleasantness unless we make the necessary changes needed. Every time I hear “stop being alarmist” I hear “don’t tell the truth”. It’s not being alarmist to discuss alarming things. This used to be an issue in meteorology. The US didn’t used to issue tornado warnings for fear of causing panic and freezing people up. Well, they didn’t know what was coming and were target practice for tornadoes smashing their towns. Yes, provide actionable info. “Go here to learn more”, “Vote for politicians who care about you and your children’s health and prosperity”…connect climate change’s shift to more extreme conditions to extremes which have already occurred and discuss how they will become normal as new extremes appear. “Yes we’ve always had droughts, but these droughts will come in more rapid succession, which is why we must have mitigation policies to prevent this from happening”. Tell people how these changes are already happening. Give people options how to act, but be real, otherwise, why should they be concerned about the issue? Especially when we as scientists get more bogged down about how everything supposedly gets attributed to climate change vs. simply providing a strong message about the seriousness of the situation, especially NOW, not just the future.
Respect goes both ways and if I’m going to respect the views of someone who doesn’t automatically agree with the science, I expect that person to respect my views and intelligence. Otherwise, I won’t trash that person, but I will move on. Some (and perhaps most) people are NOT looking to be convinced. And that’s something science communicators have to face. Not just trying to respectful, but also respecting yourself and not allowing lack of openness, compromise or cognitive dissonance stand in your way to providing knowledge. I’ve learned this from my experience as a meteorologist who are used as target practice all the time for supposedly being wrong 50% of the time (we are quite accurate), or anger over warnings (which have saved thousands of lives over decades). Climate change communicators should be respectful, be blunt, say things the way it is (consensus and personal scientific view), but not afraid to respectfully point out incorrect views and statements they KNOW are wrong and not afraid to move on if someone doesn’t want to listen. Most people will or will not figure it out on their own time, anyways.
Oh and more thing. If you don’t regularly even attempt to communicate climate change to people, don’t lecture others on how they should do it. I particularly don’t want to hear the “Now is not the time to talk about climate change” meme. I discuss these issues to people whenever I can and have encountered this criticism. If you have a problem with how its done, do it and do it better. It’s actually one of my motivations for creating this site. People who care about these issues care about the seriousness of it and the people and animals it is and will harm further. Trust me, communication is even more challenging than you believed and chances are you do not understand just how serious it is even if you think you do or even some of the latest science, which is evolving rapidly. The focus needs to be on helping the citizenry be educated on these issues so we have a healthy planet as well as defending our integrity from those who would diminish our importance in informing society.
–Meteorologist Nick Humphrey
(pictured at the top is a version of the famous “hockey stick” temperature curve by Mann 1999).
I thought now would be a good time to update on my life as some big changes are ahead. My fiance, son and I will be moving to St. Cloud, MN at the beginning of January. I’ve been accepted into the Geographic Information Science master’s program at St. Cloud State University. GISci is the study of the theory and applications of geographic information systems (hardware and software apps) for collecting, storing, and manipulating location data for visualization, analysis and modeling. I will be pursuing a second master’s degree (first is in Geosciences – Applied Meteorology from Mississippi State in 2016).
Our primary reason to move is to be closer to my side of the family. My Mom, grandparents and many cousins all live in the Minneapolis Metro area. St. Cloud is less than a hour away from where many of them live. However, I decided after much thought, to return to school for GIS because I’ve had a lot of interest in the technology and applications of it since I was a meteorology/climatology major at the University of Nebraska and there are many career opportunities for those with expertise in the technology and theory of it in many fields. Meteorology is *much* harder to get into (which I knew going in), and while I certainly am open to meteorology and experience (more on that in a bit), I want to gain much greater knowledge in a highly valued field. I’ve taken a few GIS and cartography courses as an undergrad and required intro course as a graduate student, but there is much left for me to learn which could go a long way toward career prospects. I’m doing the thesis-track option (my first masters was non-thesis), but I’m still formulating details on what I want to research, beyond ideas I briefly discussed in my graduate statement of intent.
On another note, for the 2nd year, I’ll be doing online mountain weather forecasting for the Fire Weather & Avalanche Center, based in northeast Oregon. The FWAC is a non-profit organization which does forecasting (mostly volunteer) for fire weather and snowfall and avalanche hazards, focused on northeast Oregon, although weather is discussed throughout the Pacific Northwest. The focus in particular is on back country recreation and travel. I will begin my weekly Saturday and Sunday 48 hr forecast shifts this weekend through this winter. Again, mostly volunteer, but valuable experience which regularly utilizes my skills as a forecaster. I’m hoping to have involvement in the fire weather operations next year. In the meantime, look for links to my Oregon mountain forecasts for the FWAC posted on my Twitter and Facebook feeds as they are written. The interactive mountain weather forecast page is HERE.
It will be a busy couple of months, but the changes should be very positive!
Five years ago today (October 29, 2012), the post-tropical remnants of what was Hurricane Sandy made landfall on the New Jersey coastline as a hurricane-force windstorm, causing destructive straight-line winds and historic, damaging surge from the North Atlantic extending from the Jersey coast north into the New York City Metro Area, with historic flooding of lower Manhattan.
Sandy produced widespread wind gusts of 75-90 mph across portions of New York and New Jersey with heavy rainfall totals of 7-10 inches across parts of New Jersey, Delaware, and Maryland. Storm surge was Sandy’s main cause of significant damage, with wind damage and flooding rainfall additional impacts. The post-tropical “superstorm” caused a 10-13 ft storm surge which damaged and destroyed homes and businesses along the Jersey Shore and Hudson Waterfront, with a record 13.88 ft water rise reported at Battery Park in Lower Manhattan.
Sandy’s expansive storm surge was more intense by multiple factors. As it came poleward, it grew significantly in size, a typical phenomenon for tropical cyclones moving into the mid-latitudes. However, Sandy’s weakening and mid-latitude interactions caused it become the largest North Atlantic tropical cyclone on record, producing a huge fetch (extensive wind over long stretch of open water). This fetch allowed for the building of significant ocean waves and piling up of water toward the shallow continental shelf of the Atlantic coast of the US. And although Sandy weakened somewhat and became “non-tropical”, this did not matter as the very large wind field remained and forward momentum of the very heavy ocean could not settle down in time before pounding the coastline with destructive surge.
In addition, Sandy made landfall at high tide, enhancing the storm’s ability to flood dry land areas and cause direct damage with battering waves. I will also note that this “flood reach” was even greater because of climate change-induced sea level rise. Global sea levels have risen 9 inches since 1880 and while the Intergovernmental Panel on Climate Change (UN) continues to indicate a likely sea level rise of up to 3.2 ft by 2100, many other reputable scientists have suggested the possibility of multi-foot sea level rise occurring this century as the result of exponential glacial melt feedbacks in Greenland and Antarctica. Perhaps as high as 6.5-16.5 feet by 2100 (see references #1-2 below). This, of course would be catastrophic for vulnerable coastal cities for both livability but initially for any places already exposed to storm surges. New York City is one most at risk.
Sea level rise has also been locally enhanced along the Northeast US Coast because of abnormally warm waters building offshore for years, leading to increased thermal expansion of the water surface upward. This may also be a result of climate change-induced weakening (#3) of the Atlantic Meridional Overturning Circulation (AMOC). While Superstorm Sandy wasn’t “caused” by climate change, it was part of an increasing regime of more extreme weather events (and events with with more extreme hazard variables) and a prelude to what will be far more frequent in the coming decades.
Sandy was retired after the 2012 Hurricane Season, causing 233 deaths from the Caribbean to the United States and producing an incredible $75 billion in damages (only 2nd to Hurricane Katrina). An incredible and devastating meteorological event which we can hope we continue to recover from and our country will be better prepared to mitigate against next time.