Hurricane Helene Wreaks Havoc across the Midlands & CSRA

Hurricane Helene will be a storm that many in the Central Savannah River Area (CSRA) of Georgia and the Midlands remember for the rest of their lives. This unique hurricane made landfall in the Florida Panhandle late on September 26th before racing northeastward and impacting our forecast area. This was the most impactful tropical cyclone to strike our forecast area since Hurricane Hugo in 1989, bringing flash flooding, 11 tornadoes, and widespread, destructive winds. Unfortunately, 36 people lost their lives during Helene's passage through the Midlands of South Carolina and Central Savannah River Area of Georgia. We'll summarize why this hurricane was so unique and impactful to our area despite making landfall on the Gulf side of the Atlantic Basin.

NOTE: The data provided are preliminary. They are subject to updates and corrections as appropriate. The National Hurricane Center is responsible for conducting the official post-event analysis of all tropical cyclones. Once compiled, the Tropical Cyclone Report is posted here:  https://www.nhc.noaa.gov/data/tcr/index.php . 

Helene was a well-forecast storm, with deterministic and ensemble guidance forecasting a tropical cyclone to develop with as much lead time as 7 or 8 days. We had been seeing persistent troughs in the weeks preceding this, not too uncommon for September. This made it a concerning setup to see a potential tropical system in the gulf with as many fronts and troughs as we had had. By September 23rd, confidence was high that a tropical cyclone would form in the northwestern Caribbean and move into the Gulf of Mexico.

Helene was certainly one of the most impactful tropical cyclones to impact the southeastern US in decades with flash flooding, tornadoes, and extreme wind damage noted well beyond where Helene made landfall. But what made Helene so uniquely devastating?

Up until late September, a hurricane season that was forecast to have record activity had been setting records for how quiet it had been! Through September 9th, we had only had 5 named storms for the entire season.

However, things got very busy in a hurry as the peak of Hurricane season rolled around. Our forecast area had already been impacted by Tropical Storm Debby back in early August when our south and eastern counties saw 5-10" of rainfall. Debby was the only storm to traverse the very warm eastern Gulf of Mexico, though, which left water temperatures very favorable for a strong hurricane to develop.

The atmospheric setup leading to Helene doing what it did in the Carolinas was truly unique. An anomalous trough developed in the upper Midwest early during the week of September 23, digging southward as the week went on.

This setup favored a multi-hazard, extensive threat event outside of any wind threats that Hurricane Helene would bring to the southeastern US. Its forecast track brought it through Georgia, which is a classic track for tornadoes in SC and flash flooding in the Mountains.

One of the biggest threats with any landfalling hurricane is obviously strong, damaging, straight-line winds. However, these are typically confined to the immediate coastline near where the hurricane makes landfall. What made Helene unique is that it was: a) rapidly intensifying upon landfall, meaning it would lose intensity slower; and b) moving at an accelerating pace northeastward. Additionally, it was still interacting very favorably with the jet streak to its northwest. All of this meant that this Category 4, with 140 mph sustained winds, was going to weaken at a much slower rate than other landfalling storms.

Helene was forecast to rapidly intensify over the Gulf of Mexico, despite being such a large storm. The National Hurricane Center began explicitly mentioning rapid intensification as early as September 24th. So from a forecast perspective, Helene's eventual strength did not come as a surprise, nor did its rapid forward motion.

Helene finally made landfall at 1120p on September 26 south of Perry, Florida as a Category 4 Hurricane. It is the strongest hurricane on record to make landfall in the Big Bend region of Florida. Helene had significant impacts in the immediate vicinity of landfall, including substantial storm surge. However, given Helene's size, strength, forward speed, and unique atmospheric setup, impacts extended well inland into the Carolinas and Appalachians.

Because of the jet streak & surface stationary front that were out ahead of Helene, parts of central SC and the CSRA were subject to significant rainfall well ahead of Helene. This is called a  Predecessor Rainfall Event (PRE)  and it is responsible for major rainfall events associated with tropical cyclones.

In addition to isolated areas of severe flash flooding in our forecast area, we also had significant river flooding in the week or so after Helene's passage. All of the water up in the mountains had to drain somewhere, and it led to very swollen rivers. At one point, all of our forecast points had River Flood Warnings, even our forecast point at Augusta which is very difficult to flood historically.

One of the big concerns we had going into the event was the potential for tornadoes. The track that Helene took is one that favors tornadoes in our forecast area, as the majority of tropical tornadoes develop east of the track of the center.

Guidance did a good job of anticipating this threat even a few days in advance, with Colorado State Machine Learning Probabilities elevated 2 and 3 days in advance.

We really did have quite the tornado event in our forecast area from Helene. Mini-supercells developed in the "Warm sector" of the storm northeast of the center as it pushed into central GA.

In all, there were 11 confirmed tornadoes across the forecast area in association with Hurricane Helene. These were all either EF0 or EF1 tornadoes doing mostly tree damage. Several were quite long tracked, though, owing to a very favorable environment for tropical tornadoes.

The most significant impact to our forecast area was, by far, the violent wind damage that occurred with the still-in-tact core of Hurricane Helene as it pushed through eastern Georgia. Helene was beginning to make its extra-tropical transition at this point; because of this and the other meteorological reasons driving Helene discussed above, Helene produced some of the most intense winds ever documented in our western forecast area.

When the sun rose and we began to get reports out of the CSRA, it was almost hard to believe the pictures & reports that we were getting here in the office. The destruction of trees & powerlines is unlike anything any meteorologist in our office has experienced on the job. It has been since Hugo in September of 1989 that a storm of this intensity & magnitude has impacted any part of our forecast area. Observations in GA and SC captured some of the peak winds, with numerous 60-80 mph wind gusts shown at observation sites. These point based, local observations are unlikely to sample the most extreme conditions and this was especially the case with Helene given widespread power loss along the path.

Given the magnitude of damage, loss of life, and historic nature of the wind damage, our office sent 3 teams composed of 5 total meteorologists over 3 days to document and survey the damage. We felt it was of critical importance to get historical documentation and an accurate assessment of how intense the winds were in the CSRA and western Midlands. The damage was stark, revealing a level of wind damage none of the 5 of us had ever really seen, especially at the large scale we were witnessing it. Multiple people on the surveys have surveyed strong tornadoes and were shaken by the damage. Given how rare this sort of this is, we consulted with wind and academic experts to estimate peak wind gusts as best as possible.

If you don't live in the CSRA or western Midlands, it is hard to put into words just how bad the damage was. Each of the pictures in the following gallery were captured during our ground surveys to try and convey the type of wind damage we saw.

Satellite imagery after the event has helped show the kind of tree damage to an even greater degree. Sentinel satellite data provides the ability for us to look at high resolution images from before and after the event, which revealed a really stark image.

Strangely enough, Helene was almost - to the date - 35 years after Hurricane Hugo raked the eastern half of what is now our forecast area. Back in 1989, Hugo became the modern storm of record for the Carolinas when it made landfall north of Charleston as a 140 mph, Category 4 storm. It then raced inland, sustaining its core in a similar manner to Helene and producing widespread, violent wind damage hundreds of miles inland.

Not only are these two of the benchmark storms to impact our forecast area, the setups that led to them are remarkably similar. Both Hugo and Helene had anomalous mid/upper level lows sink into the deep south & influence the track and speed of Hugo & Helene at landfall.

Much like Helene, Hugo was moving rapidly at landfall, making it much more likely that it maintained its core well-inland. The similarities between the two storms are quite eerie.

We'd like to thank our Emergency Management partners for their assistance in surveying the damage in the days after Helene & for their timely reports as the event unfolded. This StoryMap is made in memory of the 36 lives lost in our forecast area related to Helene. Our deepest sympathies go out to the families and friends of those lost in our forecast area.