Hurricane Helene has brought terrible destruction to the southeast U.S., with the worst damage and loss of life in the higher terrain of western North Carolina.
The death toll is now well over 100 and the total damage is estimated to exceed 100 billion dollars.
As we will see, localized rainfall totals for the storm were extreme, with some locations receiving as much as 30 inches.
To understand what happened, first consider the terrain of the region (below). You can clearly see the high terrain of the Appalachians over the northwest portion of the domain.
A map of rainfall totals for the event shows values reaching 15-25 inches on the eastern side of the Appalachians, where the hurricane pushed air against the terrain.
In fact, one location (Busick RAWS) had a 3-day total of 31.33 inches of rain, more than the annual total of many locations in the U.S.
The track of the hurricane was perfect for creating a very strong, moist, southeaserly flow that was forced up the eastern side of the barrier, dropping immense amounts of precipitation.
Northwesterners are very aware of the dramatic effects of geographic enhancement of precipitation: as air rises on terrain it cools and is forced to give up its water vapor, which is converted into precipitation
Hurricane Helene at 5 AM PDT on Friday still had a very strong circulation (see pressure forecast for that time below). Winds rotate counterclockwise around lows, so that the winds were from the southeast over western North Carolina
The hurricane entrained a plume of very moist air right into the eastern side of the Appalachians, something shown by a simulation of the winds around 5000 ft (850 hPa pressure) on Friday morning. The purple color indicates the strongest winds...and the wind pennants show the direction. The hurricane center was in the perfect location to push air into the North Carolina mountains.
The NOAA/NWS High-Resolution Rapid Refresh (HRRR) model predicted the heavy precipitation in the right location (see below).
Now the editorial portion of this blog.
The ability to forecast severe weather like this has gotten immensely better, with weather modeling technology enjoying profound improvement.
But even with far better weather forecasts, there are still events with large death tolls, like this event and the Lahaina wildfire on Maui.
Society must learn to better use advancing weather prediction to reduce the large death tolls in such events.
Schools, department stores, office buildings and factories are required to have clearly marked and maintained exits for use in fires. Cities that are in high-risk areas of hurricane flood and wind damage have designated "safe" places (schools, auditoriums etc.) to shelter when hurricanes are forecast. Building codes are more strict in hurricane-prone areas. Perhaps the maps have to be reviewed and expanded to cover areas hard-hit by recent storms and predicted for future storms.
ReplyDeleteRaising insurance premiums would send a message.
Noticing how each time there is a strong Hurricane, or weather event, most media outlets are quick to blame it all on Climate Change even though this year it's been a rather benign Hurricane season. Most severe weather events are just how storms track and interact with terrain.
ReplyDeleteYou notice that? Where? What media outlet blamed it all on climate change? Not the media outlets I read. The NY Times, for example, recently had an article that explained several reasons why climate change is not changing the number of storms but is making them, on average, stronger. No responsible journalist would claim that any specific weather event was caused by climate change or was proof of anything.
DeleteKeith, it has not been an extreme hurricane season so far, but I wouldn't call it "rather benign" either. According to NWS: "On average, 12 tropical storms, 6 of which become hurricanes form over the Atlantic Ocean, Caribbean Sea, or Gulf of Mexico during the hurricane season which runs from June 1 to November 30 each year." To date in 2024, there have been 11 tropical storms including 7 hurricanes in this zone, with still a month left to go in the season. Hurricane #8 is on the verge of forming in the far east Atlantic.
DeleteOn average each year about 2 hurricanes make landfall in the continental US. There have been 4 so far this year.
Come on, Bruce. Here's a non-exhaustive news article list (last 7 days). The agenda is Technocratic Marxism:
DeleteDid Climate Change Intensify Helene and the Appalachian Floods?
Hurricane Helene: How climate change is making Florida's Big Bend more vulnerable to tropical threats
How climate change is intensifying storms like Hurricane Helene
Hurricane Helene's reach shows why no place is immune from impacts of climate change
Could Helene be a sign of things to come for future hurricanes?
Helene propels climate change to center of VP debate
Hurricane Helene’s Devastation Shows No Region Is Safe from Climate-Fueled Disaster
‘Nowhere is safe’: shattered Asheville shows stunning reach of climate crisis
Why Hurricane Helene is a wake-up call
“This Will Get Worse”: Climate Scientist on Hurricane Helene
Researchers Estimate Climate Change Caused 50% More Rainfall From Helene
Abnormally warm water helped Helene rapidly intensify and suck up moisture
Four ways climate change likely made Hurricane Helene worse
Storms will always happen, if you research Hurricanes there are much stronger Hurricanes that have hit, Hurricane Camille, Andrew, Michael... etc, the debate last night, the media said storms are getting stronger from climate change.
DeleteWhat? You mean it's not because a hotter atmosphere holds more water? Here's a climate activist who says exactly that: https://www.democracynow.org/2024/9/30/hurricane_helene_climate_crisis
DeleteCliff, in a warming world, should we expect more storms like this? how should communities on the eastern seaboard prepare? is there a method to evaluate risk for areas which hurricanes/remnants commonly pass through?
ReplyDeleteWithin Yancey County North Carolina (where the highest rainfalls were recorded) is the town of Spruce Pine (pop 2,200). Through Saturday, the town received 24" of rain. Just outside of town are two mines which supply 80-90% of the ultra-pure quartz used in semiconductors, etc. The processing plants are shut down with no reopening date scheduled. The town, roads, bridges and railroads were devastated along with the homes of employees of the mines. Even better forecasting computers are needed, but much of technology development could be on hold for a while.
ReplyDeleteThe opening salvo from Nora O'Donnell during last night's VP candidate debate was "Scientists say climate change makes these hurricanes larger, stronger, and more deadly because of the historic rainfall. … Senator, what responsibility with the Trump administration have to try and reduce the impact of climate change?". This kind of junk is what the average person with no extensive meteorological or climate background will just assume is "fact", too often never to be knocked off that belief again. After all, Nora must be a person of impeccable authority as a CBS debate moderator.
ReplyDeleteBruce from the weather channel https://weather.com/news/climate/news/2024-10-01-climate-change-rainfall-flooding-helene
ReplyDeleteOr from NBC News https://www.nbcnews.com/news/amp/rcna173608. I see a lot of serious reporting that makes these claims. As Cliff points out the Seattle Times do so constantly.
Robert and Mark, thanks for those links. Both articles cited studies that talked rationally about probabilities and averages; are you questioning the science behind those studies or the news coverage (or both)? The Weather Channel article was pretty solid; the NBC article was a bit sensationalized but it did accurately quote the studies. Humans have a hard time thinking about probabilities (for weather, elections, infectious diseases, etc.), and scientists and science journalists often struggle to communicate about them effectively. It's good to call them out when they mess up, but their failures don't negate the fact that averages and expected values are changing in our climate with important consequences.
ReplyDelete**History here:
ReplyDeletehttps://www.appalachianhistory.net/2024/02/heavy-rainfall-events-and-their-impacts-in-appalachian-history.html
I'm sure they would be glad to send us some of it. We, meanwhile, are about five inches behind for the year.
ReplyDeleteFolks here have no concept of the southern mindset when it comes to hurricanes. You could tell folks the storm surge is going to be 100 feet with winds that will wipe everything off to the sand, and most folks would probably decide to ride it out. I'm from. Tallahassee originally and only one person I know who lives there left ahead of the storm. I also know several people in the Tri-cities area of Elizabethton and Johnson City, TN and none left before the storm. A massive storm in 1940 did the same damages but nobody thought it could happen with this one
ReplyDeleteDave, thanks for the list of headlines. It's not clear what your objection is to most of them. Most of them suggest solid scientific articles. A few are a bit dramatic, as headlines sometimes are, especially a random (?) collection of headlines from unknown websites.
ReplyDeleteAlso, regardless of whether those headlines represent good or bad science and good or bad journalism, I have no idea what they have to do with "technocratic Marxism" or what you even mean by those words.