There were no Wednesday, but smoke is prevalent throughout the area.

The National Weather Service has called air quality "potentially unhealthy," and Los Alamos residents are being urged to minimize exposure to it. The lab will be closed through Thursday.

A Los Alamos spokeswoman said the laboratory conducted an "orderly shutdown" of two of its largest supercomputers, 's Roadrunner, the first the in 2008, and now the 10th ranked most powerful supercomputer in the world, and Cielo, a Craig system that is ranked No. 6 on .

The supercomputer shutdowns were conducted "early on," but an exact day or reason for the action wasn't clear. The laboratory was first closed on Monday in response to wildfires that have now burned more than 100 square miles.

But smoke is a potential threat to data centers and IT equipment. It can trigger a shutdown of air handling systems and IT equipment. Particulates from smoke can damage components. And this has been a record year for smoke-producing wildfires.