Altcoins currently have a very nice growth, but these kind of markets can be dangerous, especially when one asset (BTC or ETH) can dramatically influence other prices. So yeah, I'm afraid we might be in a bubble, or at least a few corrections are needed.
Whoever was holding some of these coins from the end of February is absolutely in profit. Check out a few charts from the beginning of March, until today (May 10, 2017)
ETH-BTC
LTC-BTC
ZEC-BTC
STR-BTC
GNT-BTC
STEEM-BTC
But the absolute winner is Bitcoin. The poloniex chart looks quite healthy, but check out the long-term chart from bitcoinwisdom, with one-week candles. I wonder how high can this go!
When do you foresee a correction?
I wouldn't bet on anything, but it looks like it's going to $2000 in a few days. It can even reach $2300 or more, but the faster this goes, the more dramatic drop I would be expecting.
Thanks!
A great blockchain his Hive.
It has two base layer coins: $HIVE and HBD.