http://www.kgw.com/story/news/2015/01/17/crash-involving-multiple-semi-trucks-closes-i-84/21916981/
Black ice causes a major pileup. Beware if traveling in that area.
It wasn't closed for black ice. It was closed because they realized that an anonymous user's Interstates in Canada plan was used in real life. (Hint: It's a good thing that this thread isn't in Fictional Highways.)
With the closing of I-84 in Ontario, the plan will be reverted, and everything will be back to normal.
This isn't the first time they've closed large portions of I-84 in Eastern Oregon this winter. This happened a few months ago, I believe a couple different times over a few days. Luckily, both times I've driven this stretch recently have been fine (one time was fine the whole way, and the other time was only snowy (but not too icy, just slow traffic) between Pendleton and La Grande).