Power BI and Climate Change 2

Looking at Harvey

Two years ago, the images coming out of Houston, depicting a city submerged under water from Harvey, was shocking. New York Times had a graphic which told a dramatic story of the unfolding crisis; Fast Company called it “The Single Most Powerful Visualization of Harvey’s Impact”.

Harvey was called a 1000-year event. Then two years later along came Imelda, hitting Southeast Texas as a 500-year event.

These extreme weather events feel like they are becoming more frequent.

About two weekends ago, I did a post on finding information on climate change and using Power BI as practice to delve around in some weather data. I noted that the data I found for temperatures did strongly suggest that temperatures have been increasing but data related to hurricanes didn’t suggest an increase in number of hurricanes. I ended the post with a single map that showed the paths of all of the hurricanes, tropical storms, depressions in the Atlantic/Gulf since 1851. It was a tangled spaghetti mess.

That last graphic came from the NOAA whereas the early graphics on the hurricanes came from Wikipedia. The Wikipedia data was strictly only storms or hurricanes that hit the US so Wiki leaves out all of those storms/hurricanes that form in the Atlantic or Gulf and then meander away from US shore. The data from NOAA encompasses everything and that data strongly suggests that tropical storms in general are increasing; cat 1, 2 and 3 are either flat or declining; but cat 4 and 5 are increasing. However, most scientists say the data don’t support the contention for increasing frequency of storms or hurricanes, so I will take their assessment at this time.

The really neat thing about the NOAA data is I can take a look at a single hurricane and see how it traverses or take a look at a single season. This season (2019) there was a hurricane that was quoted as taking a weird looping path very similar to hurricane Jeanne in 2004, so that was kind of interesting to see what Jeanne looked like back then. Another year, 2005, was the year of that monster Hurricane Katrina.

But the one I’m really interested in was Hurricane Harvey since it is more recent and was dramatically off the wall in its impact… and well, it’s more recent. The photos and the NYT graphic were dramatic and compelling as a human story. But here’s the thing, the flooding was from a tropical storm, not a hurricane, that just crawled very slowly toward Southeast Texas (Houston and Beaumont). Yes, Harvey hit US shores in Rockport near Galveston as a cat 4 around 3 am Saturday, August 26 but then it rapidly decreased in intensity until it was a tropical storm on Saturday evening, around 6 pm. What this means the Southeast Texas has to fear slow moving tropical storms bringing relentless rainfalls as well as major hurricanes.

According to the tracking, Harvey lingered around the area east/south of San Antonio on Sunday and then looped back to the Gulf and headed east sometime Monday, August 28. Harvey traversed the Gulf roughly from Port Lavaca (roughly southeast of San Antonio) to Louisiana in about 2 days – Monday August 28 to Wednesday August 30. According to a news article, the rain bands started pelting Houston on Saturday, the day Harvey hit Rockport, and continuing on while Harvey traversed toward San Antonio on Saturday and Sunday. During Harvey’s trip east to Louisiana, the rain from the northwest quadrant of the storm continued to pelt the city. The New York Times graphic of desperate calls began 10pm Sunday.

I thought the storm was huge but when I looked at the data, I found the storm to be kind of small (if I’m understanding the data correctly). I used the average of the wind radii of the northeast quadrant as the key measure since this quadrant is considered the dirty quadrant due to the counterclockwise nature of these tropical storms and hurricanes. When moving counterclockwise, the winds pick up the water from the ocean and fling it on land on the northeast side of the eye. That’s why you want to be on the west side of the eye in Southeast Texas – it’s cleaner on the west side.

Imelda, a tropical storm that hit Southeast Texas two weeks ago, also was a slow-moving storm that headed straight up Houston over 3 or 4 days. Right now, I don’t have data as the NOAA’s data stops at 2018 so my facts will be hazier. I’m working off of my memories of the articles. The storm seemed to take 3 or 4 days and this time the eye travelled north, up the middle of Houston rather than coming from the west, so the northeast and east side of Houston and on through Beaumont bore the brunt of the storm. People were calling it Harvey 2 and the photos of the flooding looked very similar. Some people in the Southeast were saying Imelda was worst than Harvey.

Dorian, which was a Cat 5 hurricane, and a very strong one, when it slammed the Bahamas, lingered around the Bahamas as a Cat 5 for 2 days. Imagine the stress of spending 48 hours under catastrophic conditions. Typically, hurricanes don’t linger; they pass through and weaken, so while it’s horrible to endure, you know when the eye hits, it will soon pass over. The folks of Bahamas must have wondered when the hurricane would move on.

If the storms of recent years do not convince you that climate change is happening, I don’t know what will. The behaviors of these storms seem to be changing but I will have to continue to play around with the data, but I think our gut feel is right. The global temperatures, both land and surface sea, have been increasing. Just that strongly suggests global warming.