In an ever-growing effort to provide valuable weather information — or just a vulgar display of automated GIS skills — the National Weather Service is tweeting out images that show how many people are impacted by severe weather. The exercise shows just how little of the United States is populated.
The United States is home to over 318 million people and 2.27 billion acres of land. By 2003, we had only developed about 108 million acres, or about 4.47% of the total land area of the United States. The map above is a great way to visualize that unused land — the areas highlighted in green show all of the U.S. Census blocks that show a population of zero.
That's a lot of land we don't use, and it's apparent in the National Weather Service's impact based statistics product.
The graphics, automatically tweeted out by @NWSTornado, are mostly generated for tornado and severe thunderstorm warnings, showing the radar image at the time of the warning's issuance, the warning box itself, a population density map of the area affected, and some statistics of the areas impacted by the expected severe weather, or...impact based statistics.
Here's a tornado warning from a couple of days ago around Moline, Illinois. The warning covered 71,248 residents, 20 miles of interstate, one hospital, and 39 miles of railroad.
Here's another one covering Madison, Wisconsin. Almost 314,000 people were impacted by the warning, as were 80 public schools, one airport, and seven hospitals.
Thankfully, these are the exception. The vast majority of the 700+ impact based statistics graphics published by this Twitter account over the past few weeks affected less than one or two thousand people.
For as telling as it is that the land is so unpopulated, it's also a comforting thought that whether severe weather threatens 314,000 people in Madison, Wisconsin or two people who live in rural Butte County, South Dakota, forecasters issue advanced warning to the best of their ability regardless of population or location. The graphics prove that the agency lives up to its mission statement of, among other things, "the protection of life and property."