The other day I mentioned in passing that “official” maps of the danger zones around Mt. St. Helens were so misleading that they probably got people killed.

Indeed, I’ve learned since that they did. In fact, almost everybody killed in the 1980 eruption was in an area that government agencies had officially designated as “safe” — despite evidence to the contrary.

My comment came in a post about tsunami preparedness and “official” maps that I’ve chosen not to trust. First off, I want to say that I think “official” map makers usually do their honest best. But at best there’s a lot of guesswork involved. And before the map makers ever get their hands on the information, there can be a hell of a lot of politics in the decision-making about what’s safe and unsafe.

St. Helens, though it blew 31 years ago, offers an object lesson.

I went looking for the map I remembered. It showed a “red zone” immediately around the mountain — evacuation of residents, no admittance except by special permit) and a “blue zone” that stretched farther out (no admittance for tourists, hunters, etc. but residents could remain). The boundaries were moved several times, but they were fixed on April 25, more than three weeks before the fatal blast, and were made official by Governor Dixy Lee Ray on April 30.