You must be new. I've only been around little over a year and I've seen this level many times. If I recall correctly, the highest I've ever seen was well over 220,000 and was pretty sure it climbed higher.
Miners are switching, yes, but only because of the price. They've been switching back and forth (yes! Even BCC/H miners who supposedly want nothing to do with Bitcoin) ever since they forked away in August. Just check the hashpower charts and you'll notice the swings around the time of each difficulty adjustment. It's a pretty simple tactic. Switch away for a pricier coin, and return when the difficulty is lower, easier to find blocks.