In August is almost impossible to travel to Danakil Depression. The temperature gets high than the rest of the year. The roads also may be flooded from the rain water that comes from the highland part.
Erta Ale volcano is full of smoke at this time and its rare to see the Lava. But other sites like: Dallol Sulphur and Afdera Salt lakes are still amazing. In August the heat would be to strong and would not be easy to travel there.