The best way to protect yourself from lightning? Live in a developed country.

Last week, Rob posted a story about a Brazilian woman whose death by lightning strike was captured in a photograph. The death of Rosangela Biavati was tragic. Thankfully, it's also very rare. In fact, deaths by lightning strikes seem to become more rare the more developed a country is.

The United States is a big case study for the phenomenon, which Rebecca Rosen wrote about at The Atlantic. Early in the 20th century, something like 400 Americans were struck by lightning and killed every year. In 2011, that number was 23.

There's more than one thing going on here, but as Rosen reports, the trend towards urbanization (living in cities, rather than rural areas) and modernization (increased access to technology and improved housing, no matter where you live) is thought to play a big role. The urbanization matters because it generally means there are fewer people working in farm fields every day, and thus, fewer people outside. The modernization matters because improved technology means even farmers are safer (as with a car, the metal shell of a fully enclosed tractor cab will channel the electricity around the occupant). The same effect also probably helps explain why more people died in lightning strikes inside their homes in the past. If a house that's struck by lightning has plumbing and electric wiring the electricity can follow those pathways, and not hit people. (Of course, that's not foolproof protection. If you're talking on a landline phone during a lightning strike, the electricity could follow that wire right to you.)

It's likely that improvements in healthcare, public education, and other factors also contribute to reducing lightning deaths in more developed countries. But the general trend of "development = fewer lightning deaths" does seem to hold. Even countries with big differences in levels of development — like South Africa — show equally big differences between rates of lightning death in the relatively developed urban areas (1.5 deaths per million people) compared to the relatively undeveloped rural regions (8.8 deaths per million people). Where the trend doesn't hold true, you're also talking about countries that lack strong documentation of deaths and it's likely that there are many lightning strike deaths not being reported and tallied.

In Brazil, for instance, the best data comes from just the last decade. That makes it difficult to tie the country to any larger trends, but you can still see that most of the people who die from lightning strikes there are A) in rural areas and B) working in agriculture.

Image: Lightning, a Creative Commons Attribution (2.0) image from veggiefrog's photostream