Block times for BTC have been at 11 minutes and the backlog of transactions is slowly increasing. If we start to see miners migrating to BCH in large numbers due to profitability, there's a real possibility that those number will increase exponentially while the price falls out from under BTC.
Keep a close eye on these charts as well as the profitability:
https://bitcoinwisdom.com/bitcoin/difficulty
Something not many people think about is the fact that there's no safety valve on BTC difficulty adjustments. It's hard set at 2016 blocks which is about 13 days. If block time increases significantly due to hash rate leaving the network, the whole network slow grinds to a halt waiting on a difficulty adjustment that never happens because finding the next block takes longer and longer.
It's called a Chain Death Spiral
This is phenomenal information for anyone who is not aware.
Bitcoin Cash has a form of emergency difficulty adjustment, which is how it managed to continue being mined the last couple of weeks. Bitcoin (Core) does not, which means losing miner support is catastrophic.
Given the most recent mining profitability shows Bitcoin Cash at 140%, this could be dangerously close to happening. That 140% may not include fees and could be overestimated by as much as 25%, plus there are switching costs when changing your mining, but still...the arbitrage is already tempting.