When I used to hunt EA, we always headed there for late, pray for lots of snow !!
Only time I have seen a "migration" was when it dumped so much snow, you could not really get anywhere, a few miles up the roads was it w/o chains.
We actually stayed in the hotel in town, but there were tracks and trails everywhere, 5 foot wide trails like highways.
it got crazy just before dark, elk were everywhere !!
I did not fill my tag because I lost my mind and was flock shooting at herds, they came out of the woods, and just kept moving.
After that season, we hoped to catch it right again, but was only that one time.
Then I switched back to WA, and get rained on instead...