I know of few places like the nevada desert in the USA...I would have to think that unless he landed near some form of water he might be in real trouble.
the state of california, part of the possible area he was flying in has more water.
IF he is alive, I can't imagine him being in the desert. this has been a very dry year even by nevada standards...one small bit of rain in 85 days.
the snow on top of many of the mountains has long since melted.
two new leads are being explored...air search is hampered by high gusty winds...which in most spots wouldn't bother an experienced pilot, but swooshing over the sierra, one gets involved with turbulence and mountain wave.