The west coast is invaded all the time by drug cartels and insects all the time, damn east coasters can't a few bugs. Come to think of New York city and Manhattan are always getting invaded by stuff, damn New Yorkers.
You're probably joking, but there are just as many 'drug cartels' on both coasts. If you've lived in California your entire life, you don't even know what bad weather is like, and I'd say that's far more threatening than drugs and insects are to the general population.
On a relevant note, people who haven't been alive for this before/lived in an area where it happens will either belittle it or over react. Realistically, nobody is scared of them, and a lot of people will actually fry them and eat them. The reason it's significant is because of just how many cicadas suddenly spawn, climb up trees, and leave translucent yellow shells behind that are still left in some places for a couple years after they've all died off. They also make a TON of noise. Trees are literally covered with these things for a few weeks, and it's as fascinating as it is annoying. When I was a kid, I would smack trees covered in them with a baseball bat just becaise it was funny, and it wouldn't even make a scratch on the population of just that tree. As harmful as this may sound, it's actually extremely beneficial for humans and wildlife alike. The cicadas come in such great numbers to offset predation, and they do a good job of it. This means almost every animal in every forest of the areas affected will eat until they can't eat anymore. The dead cicadas, their shells, as well as the stuff produced by all of the animals who feasted on them will go on to spike fertility of the soil, giving way to better yielding harvests and new plant growth. It's a beautiful and disgusting phenomenon actually, to all of the unknowing and misinformed.
