The drought that has been afflicting most of the Western states for 13 years may be a “megadrought,” and the likelihood is high that this century could see a multidecade dry spell like nothing else seen for 1,000 years, according to research presented at the American Geophysical Union Fall Meeting last week.

Today, drought or abnormally dry conditions are affecting every state west of the Mississippi Riverand many on the East Coast, with much of the Southwest under long-term severe, extreme or exceptional drought conditions. Drought conditionsnationwide are down this year, but they remain entrenched in the West.