Weather

Preparing for an Active Hurricane Season during a Global Pandemic

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April 14, 2020

The world has experienced extraordinary changes in the past several months, as the COVID-19 coronavirus has inflicted severe losses in both human health and economic activity around the globe. As stressful as these drastic changes have been, those of us in the disaster science community have asked the question, “How do we prepare for an active hurricane season during this time of stress and uncertainty?” Although we may not want to consider additional stressors, like hurricanes, added to our current crisis, it serves us well to prepare for all potential scenarios, and this blog post addresses this topic.

Cloth masks attached to the faces of sculptured storm survivors at the 1900 Storm memorial on Galveston Seawall, March 30, 2020. While these masks may be considered a local artistic expression on a past disaster, it may also cause us to reflect upon the possibility that future storm survivors, in some communities, may have to deal with a natural disaster during this pandemic. Photo: Dr. Hal Needham.

Active Atlantic Hurricane Season Forecast

Let’s start by talking about Hurricane Season 2020. Early indications suggest this hurricane season will be more active than normal in the Atlantic basin.

During a live broadcast at the virtual National Tropical Weather Conference earlier this month, Dr. Phil Klotzbach, Research Scientist with Colorado State University, provided a seasonal hurricane forecast from Colorado State University (CSU). The CSU team forecasts 16 named storms, 8 hurricanes and 4 major (category 3–5) hurricanes this season. This level of activity exceeds the 30-year climatology (1981–2010), for tropical activity, which averages 12.1 named storms, 6.4 hurricanes, and 2.7 major hurricanes.

  CSU FORECAST30-YEAR (1981–2010) AVG
Named Storms16 12.1
Hurricanes8 6.4
Major Hurricanes
(Cat 3–5)
4 2.7

Forecast from Colorado State University, presented from Dr. Phil Klotzbach, at the National Tropical Weather Conference virtual presentation in April 2020.

Two main factors that influenced this forecast include warmer than normal sea surface temperatures in the tropical Atlantic and the forecast for near-normal, or slightly below normal temperatures in the Equatorial Pacific, which could lead to the development of La Niña. During La Niña conditions, thunderstorm activity over the eastern Equatorial Pacific is suppressed, reducing wind shear, or upper-level crosswinds that suppress hurricane development in the Atlantic.

Warmer than normal water temps in the tropical Atlantic, coupled with the possibility of cooler than normal water temps in the Equatorial Pacific (La Niña), have led to forecasts for an active 2020 Hurricane Season. Base map. Mark-ups by Dr. Hal Needham.

As of April 9, 2020, the most likely outcome for the 2020 hurricane season is that ENSO-neutral conditions will prevail, in which water temperatures in the equatorial Pacific average between 0.5 degrees C (0.9 degrees F) above or below normal.

“This forecast supports a more active 2020 Atlantic Hurricane Season, given the warm sea surface temperatures in the Atlantic.”

The model consensus leans slightly below normal, making La Niña conditions more likely than El Niño. This forecast supports a more active 2020 Atlantic Hurricane Season, given the warm sea surface temperatures in the Atlantic. The graphic below shows model guidance for likely sea surface temperatures in the Equatorial Pacific.

Image showing ENSO (El Niño/ La Niña) forecasts for the year 2020. The orange box roughly represents the heart of hurricane season, from July through October. The ENSO index will likely be near normal or slightly below normal, providing favorable conditions for hurricane development. Image. Mark-ups from Dr. Hal Needham.

A warm Gulf of Mexico may mean higher risk of floods from heavy rains

Those of us along the U.S. Gulf Coast have additional concerns beyond the forecast for above-average tropical cyclone activity in the Atlantic. The water temperatures in the Gulf have been warmer than normal, and this phenomenon is not factored into CSU’s tropical weather forecast. Klotzbach explained that the Gulf is warm enough to sustain tropical weather activity every year, so a warm Gulf is not likely to increase the number of storms.

Yet, warmer than normal water temperatures in the Gulf have led to tremendous rainfall totals in recent tropical seasons. Last September, Tropical Storm Imelda dumped more than 30 inches of rain across several southeast Texas counties, with a maximum of 44.29 inches recorded near Fannett, Texas. Imelda’s rains caused numerous fatalities, inflicted approximately $5 billion in damage and flooded many people just two years earlier from Hurricane Harvey.

Rainfall map of Tropical Storm Imelda indicates more than 40 inches of rain fell across portions of southeast Texas. Warmer than normal water temperatures in the nearby Gulf of Mexico enhanced these rainfall totals. Image.

Warmer than normal water temperatures in the nearby Gulf of Mexico likely enhanced these rains, as water temperatures in the western Gulf reached 86 degrees F, or about 1.8 degrees F warmer than normal, during the 2019 hurricane season, according to NOAA.

“A growing body of evidence ties warmer than normal ocean water temperatures to increased rainfall from tropical cyclones, which means Gulf Coast residents should prepare for more floods this season.”

Just two years earlier, the high oceanic heat content in the Gulf of Mexico fueled Hurricane Harvey to dump catastrophic rains on southeast Texas, including metro Houston. Oceanic heat content in the weeks leading up to Hurricane Harvey reached record levels in the Gulf of Mexico.

Hurricane Harvey dumped more than 40 inches on metro Houston, leading to numerous deaths and catastrophic losses. The storm was fueled by record-breaking water temperatures in the nearby Gulf of Mexico. Image: Shutterstock/ Reuters/ Business Insider.

A growing body of evidence ties warmer than normal ocean water temperatures to increased rainfall from tropical cyclones, which means Gulf Coast residents should prepare for more floods this season. Just one degree Celsius (1.8 degrees F) of ocean warming produces 7% more water vapor in the air, and this phenomenon can lead to more than a 7% increase in rainfall because hurricanes can concentrate moisture to a relatively small region.

While it’s not possible to precisely forecast Gulf of Mexico water temperatures for the peak of the upcoming hurricane season, through the end of March sea surface temperatures in the region were running approximately 3.0 degrees F warmer than normal, and this could enhance the impacts from both tornado and hurricane season. The map below shows portions of the central and western Gulf of Mexico observed sea surface temperature anomalies of at least 2 degrees C (3.6 degrees F) as of April 9, 2020.

Image: Sea surface temperature anomalies for the Atlantic, Caribbean and Gulf of Mexico, as of April 9, 2020. Source.

This pattern of warmer than normal sea surface temperatures in the region may be part of a longer-term trend. Consider the extraordinary increase in the number of “hot nights” observed in coastal communities along the Gulf Coast in recent decades.

The graph below shows the frequency of hot nights for Galveston, Texas, with plotted counts of the number of nights per year with minimum temperatures of 84, 85 and 86 degrees F. Note that in a time series starting with the year 1900, the first date with a minimum temperature of 84 degrees F occurred in 1927. Since the early 1980s, Galveston has observed dozens of these nights. The first night with a minimum of 85 degrees F happened in 1994; last summer Galveston observed 13 such nights. Last summer was also the first time a minimum temperature ever stayed at 86 degrees F and it happened three times.

From another perspective, Galveston’s record-breaking 26 “hot nights” in summer 2019 (combining minimum temps of 84F, 85F and 86F), outnumber the total number of “hot nights” in the 81-year period 1900 to 1980, which only numbered 23. This extraordinary increase in the number of hot nights likely correlates with record-breaking Gulf of Mexico water temperatures for island cities such as Galveston.

Source: Dr. Hal Needham (data from www.weather.gov).

Conceptually, this trend shows that hot ocean temperatures, increased atmospheric moisture and catastrophic rainfall are coupled phenomena that are likely here to increase in severity in the future. Although Galveston has not yet observed any “hot nights” yet in 2020, the city is on pace to break more records this year. It already observed the earliest calendar date in which the temperature remained at 75 degrees F both day and night, on April 8, 2020.

What does hurricane preparedness look like during a global pandemic?

With the best available science pointing towards an active and wet hurricane season, how do we prepare for such natural disasters in the midst of a global pandemic?

Professionals in the disaster science community have begun to discuss this topic. Three major themes stood out to me as I researched the impacts of this pandemic on hurricane preparedness: changes to evacuation and shelters, challenges to manage disaster response with limited resources and concerns about enhanced public and mental health issues.

Changes to evacuation strategies are a major concern, should a hurricane threaten a populated coastal area during the pandemic. An article from the USA Today Network discusses the potential need for an increased number of evacuation buses to keep evacuees a safe distance apart if evacuation orders are mandated for an infected area. The article also considers the potential complexity of evacuating patients on ventilators and trying to find them hospital space inland if they must move away from the coast.

An article in the Miami Herald addresses several questions related to the sheltering of hurricane evacuees. The article discusses the possibility of reducing the number of evacuees per shelter to increase the space between people, as well as the idea of administering COVID-19 tests or taking temperatures of evacuees.

Challenges for the ability of local, state and federal entities to protect and serve vulnerable populations when their resources are already stretched thin by the pandemic are also a major concern.

Rick Stickler, Floodplain Manager for the City of Biloxi, Mississippi, mentioned this point through personal correspondence. He particularly referenced the importance of first responders having sufficient gear during search and rescue operations in disaster-prone areas. This brings up the perspective that first responders would have close contact with the people they are rescuing, possibly placing themselves and the person needing to be rescued, at risk.

Rescue operations during Hurricane Harvey in southeast Texas. Image: Zachary West, 100th MPAD. Link.

Brandon Cook, Assistant City Manager at the City of Galveston, revealed an effective strategy to address current public works issues for the city while protecting resources for the future, should a flood disaster strike the city during this hurricane season.

“Cook is trying to handle essential public works projects with a skeleton crew, while encouraging most workers to stay home, in an effort to protect as many people as possible, should they be needed during a disaster this hurricane season.”

I call his strategy the “baseball manager’s strategy,” as he looks at city workers as key baseball players that may be called upon in a crucial game. Cook is trying to handle essential public works projects with a skeleton crew, while encouraging most workers to stay home, in an effort to protect as many people as possible, should they be needed during a disaster this hurricane season. He messaged a local resident that he is working with a skeleton crew while, “their colleagues are sitting in the dugout and doing their best to stay healthy in case they are called on to pinch-hit in the forthcoming days.”

Cook’s approach likely provides the optimal way for disaster-prone communities to maintain operations, by enabling a skeleton crew to handle the most urgent projects, while as many staff as possible work from home now, which protects the maximum amount of his people, the most valuable asset we have when disaster strikes.

Flooding near St. Patricks’ Church in Galveston, Texas, on October 21, 2019. Galveston is susceptible to flooding from both saltwater storm surge and heavy rains. Local government officials are finding creative ways to protect resources for this upcoming hurricane season. Image: Dr. Hal Needham.

Concerns about enhanced public and mental health issues, like drug and alcohol abuse, stood out as a third issue related to preparing for hurricane season during a pandemic. According to Mary Beth Treviño, Coalition Coordinator with the Bay Area Council of Drugs and Alcohol in Southeast Texas, a hurricane or flood event could have a tremendous human impact this season, as our society is already experiencing major public health and economic disasters. She was particularly concerned about people, “relapsing into substance abuse issues,” and indicated that we can already expect heightened levels of such problems without a hurricane or flood event.

Finding hope and resolve as we look ahead

Considering the possibility of a natural disaster during a pandemic may feel grim and overwhelming. We hope and pray that hurricane season 2020 considers our situation, has mercy on us and gives us a pass this year.

Yet, as I prepared this blog post, I found comfort from communicating with professionals such as Mary Beth Treviño, Brandon Cook and Rick Stickler. I was encouraged when I realized that they represent just a tiny fraction of the hundreds and thousands of local governments, disaster science and public health professionals that are operating at full capacity to ensure every effort is made to protect their neighbors.

Image of a community strength mural in Charleston, SC. Community bonds and strength that have developed during the COVID-19 coronavirus pandemic will hopefully benefit neighborhoods if they face flood or wind hazards this hurricane season.

I truly believe their heart is mirrored in the lives of many of our friends, family and neighbors who share a deep concern for each other, even if they have never worked as professionals in these fields or experienced a natural disaster. As I’ve talked to friends and family around the country, I have heard countless stories of neighbors coming together and serving each other during these unpredictable months of spring 2020. Although we may be stretched to our limits, we can only hope that spirit of camaraderie extends into hurricane season should one or more communities be tested with a natural disaster.