Sudden drop in prices with increased volume is expected.

BTCUSD

As you can see the 1H on Balance volume in the 1H chart has produces a H & S (recently there are a lot of H & S over the market - a bearish signal ). As the chart suggests there could be heavy drop. However a break above the shoulder resistance would bolster the solid gains. Better stay away and wait for confirmation to trade either ways. Keep tight stop loss. Trade Safe :)