Of course no one could know for sure but where is the potential bottom for ETH right now? Some say sub-$150, others say as low as sub-$100. BTC pumping right now despite upcoming (?) HF and ETH dumping. Seems not very logical though the two crypto-coins usually like to follow each other. Thoughts?
Some people have shifted out of alts into bitcoin to take advantage of the pump but its likely a temporary measure. I don't think ETH will drop too much more than its current level but the volatility is still high so it can experience new short term crashes.
BTC is pumping because people are feeling more and more confident that bitcoin has found a solution to its problems with segwitx2.