As noted in the press release sent out by Deschutes County:

The annual opening of the Cascade Lakes Highway occurred this morning by the Deschutes County Road Department.

Please travel with caution as there are still a few icy patches to be aware of and that no parking will be allowed on the sides of the Cascade Lakes Hwy.

Judging by the pictures of the highway I saw on KTVZ with the snow still on the sides of the road, I don’t think you could park.