The Cold Creek Fire grew up to 252 acres and is 5 percent contained as of Thursday morning, according to the Yakima Valley Emergency Management.
Officials say US-12 is currently closed, and an estimated time to open the highway is not determined.
Also, the Southeast Washington Interagency Incident Management Team says night operations also noticed a large rock on the highway.
They say crews were on the lookout for falling debris.
The Level 2 "Be Set" evacuation notices are still in place in areas around Clear Lake and Rimrock Lake.